I removed the screws (actually 4 screws) and the panel just fell off .... no double sided tape involved here.
Everything looks fine (no sign of ever any leakage) but plan to add some wood support bracing anyway. Being 6'2" and 225# I do notice the flex when in the shower. Of course, would be better if I dropped about 30-40# but much easier said than done.
.................. additional note ...........................................
I pulled the panel off again this afternoon and looked closer. Kinda hard for me to get down and really look close ...... took a flashlight along this time.
1. Everything is dry - no sign of any leakage.
2. I see clearly, the tub rests on a piece of maybe 3/8" thick styrofoam that is on top of a full tub size piece of 1/2" plywood except for the half round cutout for the drain.
3. The plywood is supported on the 'stool side' with well placed 2x4's (either 3 or 4 as couldn't see all the way to the faucet end) and the far side has wood ledges screwed into the walls to support the plywood.
4. It seems, on mine at least, the flex noticed in the tub is from the little bit of give in the 3/8" styrofoam 'cushion' between the bottom of the tub and the supporting plywood.
Actually, the construction and support system looked very professional as did the drain plumbing from the tub outlet running over to near the access panel where it drops thru the floor to the holding tank. The hole thru the floor was well sealed too so no critters could come in.
Therefore, everything is good just as is from the factory.
Hope you have no more problems with yours.