I visited a Dior boutique in Tokyo (the one facing an LVMH store), put my greasy fingers on a glass guardrail, and within 10 seconds an employee came with a spray to clean it. I apologized, he apologized back.
If you don't look like their typical customers (age, clothes, etc), you'll be mistreated or even sometimes kicked out as soon as you step in the store.
Plus it's just good practice. Your job as a salesperson in a high-end store is to educate and inform, not to sell. With that level of clientele they're looking to buy - if not now then later.
The only people who should be profiling customers are LPOs.