Earlier I posted about my tub being cracked and leaking in the front corner, after sealing that all up I kept looking under the tub to make sure there were no more leaks. I kept seeing a little water leak down under there in two places, one in the front of the tub and one on the right side (if you are standing in the tub) It took me a while to figure it out but water was leaking in behind those plastic rivet looking things on the surround that hold it against the walls, I couldn't figure out how to remove them without breaking them so I lifted the edge of the rivet with a screwdriver and pressed silicone behind them. That finally stopped all the small puddles of water forming under the tub while using the shower.
I think it is worth it to pull that plastic cover off so you can see under the tub to look around after a shower to make sure you don't have any leaks collecting under there. I probably would have never noticed the small rivet leaks, untill they rotted out the wall, if it weren't for the big leak in the corner of mine.