maybe the TD thought you were using an electronic chessboard, and wanted to make sure there's no additional functionality in it or the related software?
about the touch rule, I don't know if it really applies to internet chess, since you can click pieces as many times as you like in every UI I know.
I received the following e-mail today which puts the matter to rest:
The "help abuse" text on FICS itself is even more clear (rule #12):
It is legal (excluding with a blindfold account) to use a real or DGT (if
you can get the support) board to keep a copy of the position on (to view
instead of the screen). It is not legal, however, to move the pieces to
analyse moves that have not been played. Touch move rules are a grey area
(relying on one's honesty) as it is possible to 'hover' pieces on most
interfaces without committing to a move.
There was nothing to worry about on your part. I was handling a
"complaint" (or rather question whether it was allowed) which I
already dismissed (because of the quoted text above), but I wanted to
know why someone would use a side board and whether they knew the
rules about it.
So, don't worry. Nothing happens :-)
So there is an actual rule that is what I was doing anyway. Thanks for the input and nice to know I'm not a "cheat".