Something we tried this year for TAEA was pre-registration for some free
workshops and events. This was mainly brought about by museum events that
could accommodate only 20 to 25 people per tour.
Because TAEA has a pre-registration period prior to the conference, most of
the tickets were long gone before on-site registration occurred. This was a
disappointment to those who wanted to attend the events, but waited until
arriving at the conference to register. Maybe this will become a tradition
and will encourage members to be more proactive.
The major plus of ticketing the "for free" events was that the presenters
knew approximately how many folks would attend and how to prepare. I
haven't heard from the presenters, but I assume that from the lack of
complaints from them that this process worked well.