As a hijabi who has been through it all, the only trick that has worked for me so far is to stare right back at them. Not just the cursory glance but make sure you look all wide-eyed and look back right in their eyes. It always works, trust me. They’ll look away sooner or later.
Pakistan is the place to be oogled at by all sorts of creeps, not to mention the recent increase in passing out poondi’s with no shame whatsoever.
Once someone had managed to sneak in his card in my purse while I was waiting in line to check in at an airport there. Like a proper business card with his name and company information, and he was supposed to be a manager as well.