Non-mining full nodes have quite a bit of power if they are operated by exchanges or payment processors. If you can't spend your coins in those contentious blocks they are pretty much useless.
That's an area where I think there should be regulation:
1. Define $BTC for tax reasons
2. Ensure they don't "take the money and run".
I keep very little in custodial accounts due to the risks. It is usually 3 confirmations and out.