"These systems are put in place to protect the economy from botters and exploiters. We will close exploits as quickly as we can. These thresholds help create a safety net to keep the economy safe when we aren't there to deal with the offender," Peters says in a post on the GW2 forums.
Peters also says that the devs need to work out a few kinks, and that ArenaNet does not intend to put an end to legitimate farming gameplay. "We believe some of the threshold systems are just too harsh empirically and we'll be adjusting those systems within the next few weeks to ensure that fewer legitimate players are being impacted," he wrote.
[Thanks to Divalicious Diva for the tip!]