If I estimated my chances of being executed due to such a law were significant, it might be worth it to pay for even a small increase in the probability of it being repealed.

You could probably reduce your chances more cost-effectively by fleeing the country or taking acting lessons.

I couldn't afford to buy a pump privately before the law was changed.

You could gamble.

ETA: ...

If you decide not to do it unless everyone pays, someone invariably will fail to pay. If you allow some people not to pay, everyone will want to be one of those people. If you just ask for people to pledge, everyone will just hope everyone else pledges.