I believe there is an exception for an injured person All injuries may
mot be visible. Certainly a few questions to ascertain if a person has
suffered a concussion, stroke, or other problems with reasoning should
be allowed especially with a head injury. My wife had a stroke about a
month ago and for the first few hours in the ER, she was questioned
every 15-20 minutes or so with questions like: What is your name, what
is your birth date. do you know where you are, count backwards from 100
by sevens.
I could easily envision a scenario where the person is so drunk that
they fell down and hit their head. The person could be detained where
the officer thinks they are a danger to themselves or others