ya, a week-long ban for example. The people need to stay, but at the same time a week should be enough to let them know exploiting is a bad idea. The next ban could be a month and then three months. Discourage people from doing it over and over again while giving the dev team time to fix things.
For exploiters, as with everyone else, it will always be a cost vs benefit thing, so let's increase the cost of exploiting. Maybe devalue their skills by 10% each time they do and converting the tt value to ped which is then put in the players inventory.
This would, I think, hurt the exploiter enough to scare some of them off at the same time being mild on ppl who get banned "by accident".