Uh- gee- I am not feeling good right now. This bathroom cost us like $18,000 and no way will it get remodeled again (we are 58 and 60 and plan to sell no later than 10 years from now). We are lucky to get the rest of the house fixed up in the next few years with limited funds. Like I said, we do wipe it down every time we shower. Will think about sealing..
Like I said, KNOWING what you have and maintaining it, IS WHAT IS IMPORTANT. Prevention is FAR, FAR cheaper than a big re-do (and also better than a repair that looks like a big repair).
And the comment is right about not caulking & trapping the water coming off the wall -- except you do not have a "pan" but a tiled base.