I'm pretty sure it's a thermal sensor, so if you have hot hands you might not necessarily have to actually touch the inside door handle, just putting your fingers in behind the handle might trigger it as well. It will be interesting to see how well it works in freezing conditions with insulated gloves (or frozen hands, brrr). The manual says it might take a few seconds to register... I wonder if winter will become "fob season".

Two climate control systems, one inside and the other at the tailpipe.

2007 Camry Hybrid (in service June 2006)
FE: 6.67L/100km or 35.3 mpg (6.11L/100km or 38.5 mpg in summer)