A curfew means you have to be off the streets at a certain time. There is no such curfew. Your cousin is full of crap.
If you are talking about closing times, may bars close at 11 or 12. Some discos stay open a lot later.
A few months ago I was staying out for as long as I liked. Though there was absolutely no reason to. Nothing was ever open, nobody was out, the streets were empty. There could have been a curfew for all I knew. Sure felt like there was one. Sometimes it felt that way in the daytime, too.
"Bottom line, there is no curfew, and you can stay out as long as you like. Correct?"
Yes, though you may be the only one on the street. Vte gets pretty quiet after 11.00pm unless you go to someone's party.
Savankhet was the same way - nightlife was not very good. I've heard that since the new Casino opened it's better now, but I haven't been there since then, so I can't confirm. I enjoy quality nightlife so not having any is a major drawback for me.