It's simple if you are not allowed to leave, you don't pay. The entity is on the hook for paying is the one requiring the lockdown. The hotel takes it up with the government after it's all over.

If it's on lockdown, they aren't making money from that room whether you stay or not so really it comes down to costs. You minimize costs.. eliminate extra amenities during the lock down if needed. Cut back housekeeping if needed. Cut back free food etc