Wow, this has been an eye-opener!
I don't think any of those things are that bad, not things I would punish for, just a lecture about how I was annoyed/disappointed.
I would view the phone thing as just a silly, thoughless joke. I wouldn't punish for that, I'd just give a stern talking-to about wasting my time looking for it.
And I wouldn't put a 10 year old in time out either, and if they stropped off into a crowd. I'd just give another stern talking-to about it being dangerous and thoughtless because of the 4 year old following them. (admittedly I don't have a 10 year old, just a 4 and 7 year old.)
If someone doesn't want to pose for a photo, or go to a talk, fine by me. If the child was against the talk from when it was first suggested, I wouldn't make them go. Bit different if they had been looking forward to it but then changed their mind on the day, I would be a bit more intolerant of that.
I actually didn't realise I was such a softie. But I wouldn't make such a song and dance about something that was probably just impulsive and thoughtless. Everyone does something a bit daft sometimes.
If my DC seem genuinely remorseful afterwards (and they usually do) then that's the end of it for me.