I stopped by a Carpet One store this weekend and was looking at the LVT. The store person had a peice of CoreTec, which their chain seems to push over other brands, that they claimed had been sitting in a fishbowl for over a year. Half of the peice was out of water, and half was submersed. I pulled it out and looked at it, and you could tell both ends have been submerged, as the water staining was pretty heavy. Mold could potentially form under the product if it was not pulled up, but other than tile, or sheet vinyl, I don't think you are going to find a better product.

Does your basement flood regularly? If so I would address that issue first.

I am looking at LVT for our beach house, so when people come in and leave wet trunks on the floor etc it does not damage the floor.

What it means is, the material itself, is waterproof. It can sit IN water with no damage. It says nothing about what can happen to the subfloor beneath the vinyl, since anything that has a seam or spacing, will not be totally watertight/waterproof to the floor beneath.

Vinyl plank is water proof. It can sit in a bath of water for months = no issues (other than algae and mold growth). It STILL has to have a vapour barrier. And standing water is something that needs to be avoided like the plague (sump pumps, drainage updated, eaves/roofs dealt with, etc). Even if you have water in there for 1 day, how likely are you to "save the floor"? My estimate is you have a 10% chance of saving it. The other 90% is you will require a new floor.