Inclement weather, illness, time off?

Hi there, curious how a sitter should handle situations regarding horrible weather or illness, etc preventing a visit from happening on a particular day, a situation that is not planned for, perhaps happens at the last minute. Example, car trouble, snow storms, sudden illness or other emergencies? Of course notifying the owner as soon as possible is of top priority. But when scheduling a visit or a stay do you discuss a "Plan B" of sorts with the owner before such situations arise? I wouldn't feel comfortable raising such a question when first meeting a client as it may sound like I'm already skirting the commitment and responsibility before I've even started the assignment.

So I guess it's multiple questions: 1) Do you establish a plan or an understanding with the owner beforehand? If so, what are some suggestions on how to approach this and some possible solutions?

2) If you just can't get there for one urgent reason or another, does Rover need to be contacted?

Thanks in advance.