I threw this out there just as a mental exercise, see what kind of input I would get.
Yes, the only ones who care would be the dubs, so a simple message pointing to a site such as jwfacts.
No, it is surprisingly inexpensive. $10 US buys over 200 imprints, depending on time of day. Each imprint last only a few seconds each, so it can't be wordy.
I would target two boards on two major interstates in the area leading to the convention site, targeting 730-930 am Friday morning and an hour or so after the session, maybe with a reference to the days theme but with a twist.
If WT got wind, maybe they would waste a LOT of money buying all the ad time...ha.
Anyway. Look up the site or similar in your area. Might be fun just to play with.
Snakes