In this situation you are advising a person not to be naked in a hotel that you have paid for the right to be alone in and be protected from the outside ... not a person standing naked at a subway terminal.
Harm vs. remedy? Weird that you somehow modify it with "celebrity", why should a celebrity have any different status? Why would peeping on Jane Seymour in her bedroom be any different than peeping on WWJD in his? What is the harm? I'm still not sure where you are serious. The protection of privacy is one of the highest priorities that I believe we have. So much so that we are a people hell-bent on ownership of individual property in order to protect that privacy. We are not a shared-culture like some others. If there is no harm in a celebrities private pictures, there is no harm in ANY privacy case, not medical records, not academic records, not voting records, nothing. They are literally laid bare for all to see.
Of course the renting of the nearby rooms isn't wrong nor is there any reasonable allegation that it is. That is the strangest of straw men I've seen you throw out. It is evidence of intent, but nothing more.
I'm still not sure why you think peep holes, or altering peepholes is only "arguably" crossing the line. Also, I'm not sure why you'd even approve of heat imaging of a person in privacy, or anything of the like. For a person that complains about the NSA/CIA/government surveillance, this is an extraordinary position to take, that the government can't do something that you, apparently, readily believe the general public should be allowed to.
To make comparison:
This would be outlawing searches by government under the 4th Amendment, yet affirmatively allowing private citizens to enter other people's property whenever they wish, because they can't "own" space. I don't think you can reasonably restrict the government from doing something you believe everyone can do otherwise. That wasn't why the 4th was adopted, it was because we didn't want the government to do things we couldn't do ourselves, a legitimate fear when discussing government.