Easily can point out bots on my server, just to have fun with them I set the price to one above the vendor sell price (430-ish gil) on an item that is going for about 200k on the market board. Within one minute the seller had lowered their price to nearly 100k. No human micromanaging the market board would do that (instead they would just buy the 430 gil item), so I bought his half price item and am now reselling it.

Makes it extremely difficult to sell stuff on your own though. Obviously this behavior should 100% be acted upon but also honestly I'd like to see buy orders so there's less 1 gil undercut competition for people who don't mind coming down a little to just go ahead and sell their stuff.