I have no idea if I'm missing something obvious here, but as far as i can see there is no way to check writs you are receiving via the above method. The other day I bought a 150+ voucher writ and when i received the writ I had no way to check that i was receiving the writ I agreed to buy. When i viewed attachments, It merely stated cloth writ '0 vouchers'.
Accepting the trade was purely a shot in the dark as i had no idea if I was actually buying a 2 voucher writ or the 150+ voucher writ I agreed to buy. Didn't get scammed because I did receive what i was promised. But if there is no way to check writs this can easily be abused. I'm on console if that makes any difference.