Can people judge others by their cover? Like how they present themselves and dress? Like if guys wear pink clothing, they must be gay? Or if girls wear ties and boy clothing, they must be lesbian? Or can it just be a fashion trend?
It really varies ..it depends on the individual am looking at. Some of my guy friends do wear pink clothes but I wouldn't think of them as being gay because they don't act like it. I think there is a difference between one wearing something that projects a particular attribute and one acting in a way that projects a particular attribute.
People CAN judge, but that doesn't mean it's accurate.
Some things are safe assumptions, like if you see a girl with tons of make-up, hair extensions, fake nails, extreme tan, etc. you could probably infer that she cares a lot about her appearance.
But some things, like sexual orientation (as you mentioned), are really personal and you usually can't tell. Everybody thinks I'm a lesbian because I wear plaid flannels sometimes. :P And I know straight guys who wear pink.