You can actually do this without addons or bots. Sure, they make it much easier and time-friendly. But, the way Auctionator/the default AH UI works makes this exploit possible.
Blizzard could consider making the default list price be the 95% or 99% price based on total volume, as opposed to just listing at the current lowest unit price (this is where the scam/exploit happens). But that might be prohibitively expensive/impossible to calculate client