The easiest way is that restricted accounts can’t use the market. It turns out that almost all bots are currently free accounts and the only way to profit is to reach level 50 and then use the market to trade gold.
While im sure they are after those as well, and anything sellable thats easy to get i would bet the reason for the mass influx is the raw gold from the express pass.
I do hope AGS and Smilegate can work on a solution quickly on the bot situation. It is unfortunate that any event that will benefit for us will also benefit the bots