@Charlie: Hard to avoid scantily clad women in the hot summers. I always have a sefer and or an audio shiur with me when I take subways and buses to keep my mind on the kadosh rather than the chol.
Actually, you have to be careful learning in front of something that may be considered an ervah. I know somebody who learnt every day on the subway, and was told by his rav that in the summer, he should make sure to stand and face the wall rather than sit across from an ervah, and not just because of Shmiras Eynayim; you may have a problem with Hilchos Talmud Torah. I advise you to ask a rabbi.
@Gavraatwork: mw13 – AYLOR
@Apushateyid: doesnt sound like OP is actually asking a question.
You apparently missed the point of the thread. #KTCRIM (+1 to mw13!!)
mw13 – 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.
I know quite a few people who take off their glasses in the streets in the summer. Not gedoilei yisroel, not chassidishe kedoshim, but regular Litvishe balabatim who don’t see the need to see everything that crosses their path. If your eyesight is good enough that you won’t bash into lampposts, you can do that.
As for cleaning ladies – I don’t know the American industry, but in London it isn’t such a problem. The majority of cleaning ladies are Romanian, Polish or otherwise European, and a lot of them are religious (in some way or another). They often dress more tzniusdik than many frum ladies. And the ones that aren’t are generally sensitive enough to know that they must dress modestly whilst working.
I don’t see how anybody would be able to draw a line, as you asked. At least in principles, any self respecting Yorei Shamayim will tell you that he wouldn’t compromise standards. In practice, however, it is easier said than done.