While it may or may not be "a problem" for Safeway employees. it does set a precedent. Having worked for several different retailers, I can tell you that some big box discount retailers will follow suit.
Also, what if no employees volunteer? This isn't so far fetched. Most retail employees look forward to Christmas off after the long and late hours. Retailers would then simply schedule people, half of whom won't show up. You're right about a skeleton crew.
The retailers I worked for didn't pay overtime for holidays{non-union.} You got the day off with pay but had to work the day before and day after the holiday. If you worked the holiday, you simply got an extra day of pay. Of course you had to be full time.
I've heard that both Walmart and KMart are considering this. Having had to work 70-80 hours a week on a retail manager's salary at Christmas, I looked forward to the day off. It's the manager or assistant managers who will be stuck working that day.
So, think of us when you run out for that item you forgot.
I'm not even going to be in the country this Christmas, so I won't be patronizing any American business that day. I guess I'll have a guilt-free Christmas.