I notice when anyone wears the really big ones, but I don't really care. If I noticed a guy wearing them, I would be happy for him for looking how he wanted to look despite what others might think. It wouldn't change my opinion of him in any negative way.
Fake lashes are probably the most obvious thing you can wear in your face so yeah I would definitely notice. I would probably be amazed for a moment but that's about it. I'm not a big fan of false lashes tho, be it on men or women..