oil pan gasket ... is it leaking?

I've got a 1998 Honda Civic EX.  The dealership told me my oil pan gasket was leaking, but that I could drive it until the next oil change.  I said that I had just had the gasket replaced 17 mos ago; were they sure?  Yep, they were sure.  They told me to take it back to the shop that had replaced it and try to get them to do it again for free (even though it was out of the warranty period by this time).

I took it to the shop that had replaced the gasket.  The guy called me out to look at the car while it was up on a lift.  He gave me a flashlight and said the gasket definitely wasn't leaking.  I could see a tiny bit of shiny black rtv but no oil.

The dealership told me they had had trouble putting the drain plug back in and that soon I would need a Time-Sert or a new oil pan.  It occurred to me that maybe they had messed up the gasket seal while working hard to get the drain plug back in, but when I suggested this to my local shop guy he said, "The gasket isn't leaking.  It's fine."

What's going on?  Both shops have a good reputation and I like both mechanics.  Neither shop seems to have a reason to be dishonest here--Honda told me to take it back to the shop that had done the repair and try to get a free fix, and the local shop actually showed me the car and didn't try to blame the problem on the dealership.  They insisted there is no problem.

I can check my oil every week and see if the level goes down ... but what's going on here?  A leaky oil pan gasket seems pretty easy to diagnose.