To be honest, never felt the need to tie my hand saw to a lanyard. Nor have I ever seen a climber doing it ?
I have often thought it would be handy to have a wrist lanyard on it, you know like a camera, or a Wii remote has on them, that way you could safely open your hand and let the saw 'dangle' as it were.
The two or three times I have dropped my handsaw my groundie simply tied it on to my rope and there we have it.
Not trying to say anything about anyone who would lanyard their saw, just being honest in that I haven't ever felt the need, might try it though if I was in a tree that was going to have a lot of handsaw work, but in that case, generally out comes the 020(or MS200t or whatever the heck they are calling the arbor saws now).
Take care Jim, and stay safe.
-Grais.