This sounds as if it is a custom from the U.K.
So, can someone explain what is celebrated on May Day?
is it a Pre-Chrisitian rite of Spring?
International Worker's labor Day?

We used to make baskets or origami paper containters
and fill wioth candy or violets and hang from door knobs
and run away....that was how i remember celebrating may day.

then there is the signal "May Day, May Day" which means
help! save us! (or "Our Ship is sinking")