[runnerup]

It's a minor procedure but it involves sedative / light anesthesia. Basically I have to get my lower GI tract investigated for pre-cancer every year and they try to remove any faster growths. Nothings ever turned up malignant yet, but it's an annual check-up just in case. They give me some light sedative while they put hoses and tubes in my rectum. Perhaps I could forego the anesthesia, I haven't asked.

The "we can't let you drive yourself home" policy is always due to anesthesia/sedatives. If you're not receiving those then you can drive yourself.