Turn and Bank indicator and competition

I have a turn and bank indicator installed in my glider. I would like
to fly in a competition this year and I read somewhere that this kind
of instrument is not allowed to be used during a competition flight.

The question is; do I have to remove the instrument all together or
can the competition director seal the switch in off position or cover
the instrument and seal it? I don't like to remove the instrument
since it can be a safety device while wave flying in anything less
then perfect weather.

Please note I am not asking if I should ever use this device that is
not the question. The question is simply interpretation of competition
rules and what does happen is a situation like this?

Thank you in advance...