It seems like it would be an improvement to either:

1. Keep the very short notification period but also try to reach the site owner via phone or IM

2. Lengthen the notification period if using email only

(Note that I have no problem with short notice and email only if the customer was given the option of providing an emergency contact method but chose not to, and that I otherwise generally agree with the response.)

It seems like the real flaw here is the combination of lack of communication and lack of warning.