So I ran into an interesting strategy on the market board yesterday. I've been trying to sell an HQ item that should sell, but won't. When I checked the going rate, I found that someone had put 100 NQ listings for the item on the board, so as to push off any higher priced HQ items. The market board is capped at 100 listings per item.

This seems like shady/brilliant way of abusing in-game mechanics, so I wanted to ask if this is a legit strategy before I push him off the market board the same way. I'd rather not get banned, cause again... shady/brilliant... but in-game support said to ask about it here.