I am the guild master of a trading guild, long story short, as i was bidding for traders as usual, until i noticed we dont have gold anymore, then i realized on one of the bids i had put one extra digit without knowing it, which made me pay 10 times the normal price, and emptied the whole guild bank, and there was nothing i could do.
First lets talk why this is bad design, and insanely so:
In case designers at Zenimax dont know this, when you have to do a boring routine thing (like bidding) your brain starts automatizing the task, so you can have your attention on more interesting matters, therefore you pay less and less attention, and finally, you will make mistakes, this is one of the fundamentals of UX design, humans make mistakes, specially on boring tasks, and the game does absolutely nothing to prevent the mistake, and 0 ways to correct it. and we are not talking about something you get to be very patient with, you have to bid 10 times every single week, all manually, it didnt happen for me for 2 years, but now that it did, i either have to farm gold and loan money like crazy, or disband my 2yo guild because of one wrong keystroke, a guild gone for one wrong keystroke, it could even be more dramatic had it been a bigger guild, would 100 million gold make designers do something about this ? this is as much as you could lose if you make the same mistake on a craglorn trader.
And a wrong keystroke is not the only way this could happen, lets imagine i have 3 guilds, 1-"Cool kids" 2-"Cool erp'ers" 3-"Cool traders" and i am a member of the first 2 and the guild master of the third, when i start bidding, my default guild is "Cool traders" because i have no rank for bidding in the first 2, but if i become an officers of "Cool kids", my brain being used to "Cool traders" as default will start bidding without changing the guild, but the game has now changed the bids to "Cool kids" simply because it is my first guild, and i can end up wasting somebody's money, even if i notice it a minute after. sorry cool kids.
Now lets see how easy it is to prevent this:
I am not a ZoS game designer and thinking about this in an hour i can come up with 10 ways to prevent this but for those who do not know, any stress put on servers is there for when the bids get calculated, thats on tuesday evenings when its decided who gets what trader, so none of my solutions make it harder on the servers, not drastically at least.
1- why can we increase the number of a bid, but not decrease it? nobody can see the bids, and you can increase it, so we cant argue that whole system is built around fixed numbers, why cant we decrease then??
2- lets imagine decreasing bids go against their design goal, for whatever reason, how about being able to delete or decrease bids for 30 minutes after putting them, that way its no longer a system to use, just a way to correct mistakes with.
3- okay lets imagine even 30 minutes is not acceptable, how about an option where you can limit your own bids, a box that you put "5mil" in it, and any bid above 5mil will not be applied anymore, its easy to implement, and it puts no pressure on server, it doesnt change anything about the bids, just a controls the amount you put in there, same as you not being able to put more than you have for example.
4- why do we pay upfront for every single bid again? its not like we can win all, if your trader costs 2mil, why do you have to have 20mil to bid on 10 of them? wouldnt it be a better system if we had to bid on each trader just below our money, and when we won the trader, when we would pay? this way we could self-control the mistakes, by not putting high amounts of money in guild bank when bidding.
5- even if all these are too hard for ZoS to implement, how about a disable option? where you dont change anything about your bids, you just have a button to disable them, meaning you dont get the money back either, it just works same as you losing the bid, if you bid 10 mil on one trader and 8 on another and win the 10 mil one, your 8mil bid will get disregarded even if its the highest bid on the trader, and the money will return to your bank on tuesday, you could imagine the "disable" button to work exactly as the 8mil option, it just gets disregarded, for those who think this is hard to make, i am a programmer and designer myself, all it takes to implement is checking another condition for each bid, and even if we have 2k bids on each server every week, thats only 2k conditions being checked, nothing for a server to work out, at least nothing to slow it down or bug it out, unless they have done their bid-checking algorithm so wrong that it checks every bid more than once, which could be the case seeing the number of times the bid system bugged out on PC-EU.
5 Solutions, and not utopian all in solutions, these are functional and easy to create options, which if ZoS cares about their UX, takes no resources to create. and no more guilds have to be disbanded because of simple mistakes that WILL happen, that is why you have a "lock" option to not destroy your items by mistake, and a "buy back" option when you sell something by mistake, we are humans ZoS, we are not supposed to be expected to be 100% perfect when dealing with the game.

In regards to different guilds, the easiest solution is letting us put a default guild for bids, its even useful for when were choosing which guild to list our items in, im sure most of the people reading this have listed an item in the wrong guild just because its number 1, and have had to cancel, change zone to a get a mail, go to the bank, and put the item again, how about a "NO".

I hope somebody at ZoS reads this at least, but either way thanks for your time if you read this.