My wife (late 20s) did a lot of traveling for a former government job and tended to carry a backpack and dress casually when doing short trans-con trips. Never had a problem when checking into nice hotels for what it's worth.
On the other hand, she always had problems with airline ground staff who just couldn't believe she was 100K and tried to block her from using Elite check-in lines or the Red Carpet. Friend of hers about the same age was actually refused service by a ground agent when he tried to check in with a first-class upgrade. Had to call for a manager to sort things out.