One two-region bucket would be cheaper than two one-region buckets. I’ve done analyses of similar systems and calculated the costs necessary.
You pay for durability and availability in the form of disk overhead, CPU, and network. Each encoding scheme has some expected cost. If your overhead for one-region is $X per gigabyte, then generally speaking, the overhead for two-region is going to be less than $2X—each region is more durable + available because of the copy stored in the other region.
You haven't worked with many contracts, have you? Unenforceable clauses are the norm, most people are willing to follow them rather than risk having to fight them in court.
Typically there is no penalty - and contracts explicitly declare that all clauses are severable so that the rest of the contract remains valid even if one of the scare-clauses is found to be invalid. IANAL
Have you read the actual document or contracts? Opining on stuff you haven't actually read seems premature. Read the contract, then tell us which clause violates which statute, that's useful.
