Yes, but it's always always better to have a policy in place than to make one-off decisions.

This isn't always feasible or practical. People can't always foresee the future (otherwise gambling wouldn't be a thing). So we can't assume that a policy can cover every possible scenario that might occur. Things happen that practically nobody thought might happen. This is why "escape hatch" clauses were invented--to give parties a way out in the event that the unforeseen occurs.

I think the idea is what once the unforseen does happen, that you encode the decision you made into the rules.

Yeah that would be better, people should be able to know in advance what they're not allowed to do. I was just pointing out that they've done it before.