As others have already pointed out, it's illegal to block them in. Seems if you park on someone else's drive, you have that someone else wrapped up in a neat little bow - they can't touch your car, and they can't block you in
It's illegal to block someone from leaving.
LOL.
Not entirely sure on the rules for that one. A proper bus company needs to have off-road parking with planning permission. Dumping them on residential streets will swiftly see their operators license revoked.
Only an issue if it's done by a bus company. If it's a privately owned vehicle then there's no op-li to worry about.