Other chains overbook, too.
I once booked 2 rooms at a Jury’s Inn in Ireland, where we were attending a wedding. I booked well in advance and told them we’d be arriving late, after a Friday evening flight from London.
Plus, on the very morning of our arrival, I phoned the hotel specifically to remind them that we’d be arriving some time after 10 pm.
When we arrived, our rooms had already been taken! 🤬
Even I wasn’t as incandescent as the Irish friends who’d been waiting for us in the bar!!
The staff did find us alternative accommodation, but needless to say, I will never book a Jury’s Inn again.
OTOH we have stayed many times at Premier Inns, and have never had any problem.