I’m 64 with no personal “risks”. Went to Walgreens and told them household family member was a nursing super at local Veterans home (the risk). Got the shot, no questions. Just be truthful and tell them your concerns. Appears to me if you are close in age they will booster vaccinate. If you are 30, without risks, probably will need proof. This seems to be done locally on an honor system with no verifications. Same for my wife who is 61(has valid personal health risks) but no one called her Dr to verify shot eligibility.
I initially had a concern of not wanting to take the booster over someone totally unvaccinated needing it, but, SCREW them, they’ve repeatedly had the chance by now. Too late for me to care. They can sleep in that bed they made and roll the dice..,