Yes, they suck.
Yes, pretty much every member that see's them does /no, /sigh or /slap in their direction (i'm a fan of the /no myself).
Can we stop them? Sure with lots of mass camping of the NM's they camp, stealing the mobs they get drops from ect. ect. Whether this will actually make them give up is only a geusse. We probably arent aware of half the gil sellers, not all have obvious names.
Will this happen? Most likely not in my opinion.
All/majority of games have exploiters (is that even a word! ><) it sucks...but we do have to deal with it.