My 04 MDX is throwing the P1454 code (by itself, which is nice). I would like to replace it myself, but don't have time for a week. Would there be any harm in light daily driving for a few days before I can actually get the time to replace the sensor?
I personally wouldn't worry too much about it. I guess that it might be prudent to stop after a few minutes to see if there is any unusual pressure building in your gas tank by removing the gas cap. If not, I doubt you're going to hurt anything.
The evap systems are (IMHO) far too complicated for the slight amount of benefit they might actually provide. Solenoids, valves, carbon canisters, special gas caps, and a couple miles of tubing. I'd bet more gas is spent driving around trying to get the systems working than they ever prevent from evaporating into the atmosphere! ;-)
Fixing an evap system often involves a voodoo ceremony and sacrificing a couple goats, so be prepared... ;-)