Just wondering, what is the use of gear pins?
The pins are there, as you suggested, to stop accidental retractions on the ground, this is kinda embaressing to say the least. As you mention they will get you in trouble if you dont do a good preflight, but not as much trouble as a wheels-up on the ground.
If you do misthem, simply land again and sort it out.
Used to be a fairly regular happening on the mighty Fin!