If they don't have a working smoke alarm, or are storing flammable materials over the burner, or don't have enough emergency exits then no, they should not do reservations at all.
It seems Canon did not have a backup, they had replication of data. If you are storing data for money, then this is a professionally negligent behavior. Not being able to prepare for everything is not an valid excuse to not prepare for what you reasonably can.
What does adherence to fire code have anything to do with taking reservations?
Also, reservations are free. It's not reasonable to expect restaurants to do anything and everything to honor 100% of reservations when many customers never show up for them and don't have any skin in the game anyway. Whatever point is trying to be made here is going out the window thanks to the "zero 9" nature of restaurant reservations. (Yes, not even 90% of restaurant reservations end up turning into actual paying tables.)
Indeed, it has nothing to do with taking reservations, but providing service which is the crux of the issue. If they accept customers while knowingly not following fire regulations, then yes, it’s wrong and unethical; similar thinking should apply to software services.
It seems Canon did not have a backup, they had replication of data. If you are storing data for money, then this is a professionally negligent behavior. Not being able to prepare for everything is not an valid excuse to not prepare for what you reasonably can.