Of course, there is chiyuv lehalachah – not just a nice minhag, but a chiyuv – to avoid any unnecessary interaction with immodesty. Going to a mixed beach where there is certain pritzus is assur for any Jewish male. I think the only hetter is going to be ?? ???? ??? ??????; if it is possible to order clothes without going to a shopping mall in the summer, you may well be mechuyav to do that.
Agreed. The question, how do we define “unnecessary”? For example, what if I can get a nicer or cheaper shirt in the mall?
I don’t understand the doubt. Is there really a question whether it is permitted to violate shmiras einayim in order to secure a “nicer shirt”? That’s a “necessity”?