Wow...11 pages re: missing rehearsals, that's some traction! Not sure if the subject is primarily about someone not showing up, or if whether a pet's death is a valid reason. Anyway, my .02:
As far as the deceased pet scenario, people react different to tragedies, car accidents, traffic tickets, job loss, loss of loved ones, inc. pets.
Some need their space to mourn and reflect, others (like myself) prefer to get back into the fold to take some of the trauma away. 2 each their own.
As far as missing a rehearsal in general, a lot depends on what the project is. Missing a paid rehearsal is one thing, some B/L's would not have it, others would allow it depending on the circumstance.
If it's a matter of missing a "Band Practice", IMO the biggest consideration would be the amount of inconvenience caused to the other band members who kept their schedules free to show up.
Finally, for those who disdain rehearsal in general, or consider it irrelevant or amateur- Whatever. Personally, if I'm performing material I like with players I like, I totally enjoy that time, and going over material sure isn't going to make it sound any worse!
There, I have contributed!