I was kind of joking about the duct tape!
If I was going to do it, I would do it right.... Buy some black corrugated plastic, cut a square piece big enough to overlap by 1-2", cut a hole for the tubes, then fasten to the existing material by drilling little holes and using plastic rivets (3/16") in the holes.
Then I would use spray-in expanding foam around the tubes to seal the deal.
Of course, that's probably what the dealer will do... I might just tape it so no little critters find their way in before I take it to the dealer...
I have a list of a few minor things that need to be fixed, as well, so probably worth the hook-up and 30 minute drive to the dealer. Besides, I want to buy some sink inserts/cutting boards, there's not enough counter space in the kitchen for an all-out cooking extraveganza!