The good old proof of passage on an Audax.
We once used Drew Buck who was the speaker at the AGM as proof of passage, had the dinner and still made it round in time, just, much to the then DIY organisers amusement. Mainly because he saw how much we drank during the dinner. Memo to secretary never sit on Hummers table again.
Remember it's only a bike ride, don't get hung up on proof of passage there are many ways to prove you where there, lets face it at times easier than proving you weren't there!!!!!!