We've experienced the tech's keyboard inputs not being recognized on a couple of occasions with unattended installations. It isn't very often, nor is it reliably reproduced.
The local and remote machines were both running XP.
Disconnecting and reconnecting did not resolve the issue, so the remote machine had to be restarted, and things work properly.
We are running: 2.3.2005.4303 The tech and the SC server is local, but the remote computer is at an offiste facility.
I haven't heard many concerns lately about it, so I think the frequency is quite low.