In fact I've seen some very strange behaviour.

I doubled one opponent when I had only a few pieces left and he still hadn't borne any off (but there was no way I could gammon him, before anyone asks).

Not only did he accept but doubled me right back next turn to make it an 8 point game (in a 7 point match). Of course I won easily.

I urge people to read and understand the rules. Ask for clarification here if necessary.