OK so this whole sandbagging debate has raised a question: Someone raced
for several years (say at Cat 3 level) but has not raced in a few
years - what category should they begin racing in?

As far as I have understood it they must start over again at Cat 5 (Cat
4 for women, bottom Cat for Masters) in which case an experienced racer
is bound to be accused of sandbagging. Is this the case? Or can you
elect to start in a higher Cat? If so what evidence would you need to
prove your case?

What is the protocol here?
Vicki