Hackers have a 6 months minimum ban length or so and it's already a perma ban. That's why we have unban appeal for that.
For this, well you got a good point if the players here are rich people. Most of the players here don't have work or what we call minors. Some can ask their parents to donate, some who can't. We should consider them, people who quests, plays ctf/infected for level 99 to rebirth just to buy and have donors.
I think your suggestion doesn't make sense and will just keep players quitting the game. You should also think about the disadvantages.
And I have to agree with Dave's reply;
When people use hacks, it doesn't matter if they use donation items or not, they will have an advantage either way so I don't see how this makes any sense.