Yes, big debate, I have always purchased in UK, and had any adjustments done here, but I have problematic feet apparently
I have witnessed poor practices in european ski boot stores, when a ski shop rented my OH some womens' touring boots 2 sizes too big. He was comfy for 1 run, but the subsequent sores lasted 2 weeks+
Coincidentally, another store in a different resort tried to sell him some womens' alpine boots 2 sizes too big.
And, no, he does not indulge in x-dressing
If you want to buy in resort do lots of research, know your size and foot shape.