Should I be expected to stay another night?

Owners booked me up until today, their flight was arriving at 10:45 pm and they asked me to stay until they made it back, now their flight is delayed and they aren't expected to be home until after midnight. Should I tell them I will leave their keys and garage door opener inside or should I offer to stay until they get home, but charge them an extra night. 10:45 is late for me let alone after midnight, these are my only clients that request for me to stay at their home until they make it back.