Just wanted to note that the videos you were looking at probably were made pre-Justice System. There was a time when no containers were owned, thus no stealing, so one could loot containers in towns to their heart's content.
I recommend looting throughly delves. There are a few out there with great numbers of ingredients. Spend a day looting crates and sacks and then pump those into recipes. It takes a bit to build up a stockpile of ingredients, but it's much better looting everything while your grinding/questing than to go out looking for that one uncommon item you need.