What we have done at some other events is have Forum labels, where you can write your Forum name so people can say hello. We can provide the labels at an 'agreed location', if people were willing to wear them?
We could also arrange to meet at an 'agreed location' at a specified time but that does not always work if people get tied up and can't make the agreed time.
Having found the cars parked which belonged to Forumites, it was slightly frustrating not to be able to meet the owner!
Sounds good to me. Like you I was hoping to meet other I've corresponded with online, in most cases I found the cars but couldn't associate them with an individual. As you said, frustrating.
Regarding the video posted by MrKinsey, it was nice to see Chris Done captured on film (film? - showing my age a bit) doing what he does best with a V8 and also at 5 minutes 30 seconds in, an Aston with a square steering wheel. I remember the derision that greeted British Leyland (it might have been BMC back then) when they fitted a square steering wheel to an Austin Allegro, it was sufficiently strident for them to remove it. How things have changed.