I've had a chat with a number of people heading over to France from Goodwood, which is quite a common stop-over en-route, and I'm looking forward to doing it myself at some point.
Attitudes seem to vary greatly from person to person - you'll see some people going as if they were off for circuits, while others go in full immersion suits with liferafts etc. One party of four in immersion suits were heading off in a Warrior on a roasting day last August, and looked more in danger of death from heat exhaustion than anything else. The general view seems to be that problems are unlikely (just like any other half hour in VMC) but that a low-wing retractable-gear aircraft is probably best, assuming you have a choice. Nobody likes the idea of ditching in a fixed-gear aircraft.