Sounds like you not only haven't worked retail for the past several decades (if at all), but also didn't pay attention when the Supreme Court addressed this very issue recently as well and UNANIMOUSLY AGREED that people aren't entitled to get paid for this time.
So Apple's a bad retailer for using the same procedures in their stores that every other retailer does?
So you want the store to pay your daughter more than the others who work there because she made plans after work which have absolutely nothing to do with the store's function or her job.
Why does your kid deserve more money because she chose to bring a personal bag into a retail workplace? Is she a princess or somehow special? Should everyone else ALSO stay on the clock and be forced to hang out to accommodate your daughter's time waiting because SHE decided that she just HAD to bring in her bag to accommodate HER plans?
Or even worse, why should your daughter basically get to stop working before the others on the shift and NOT do the work the entire time she is scheduled? Why should everyone else have to work their shifts end-to-end while your kid gets to stand in a line and NOT work for the 15-20 minutes? Oh yeah. Because it's a party or something and it's just that important.
No. You can either deal with it, or get another job. Same as everyone else in that industry. You don't need to bring that purse to work. Use your pocket, and if it's too much to handle, get a different job.