That's correct... and interesting about your friends! The other thing you're not supposed to do (at least, in Asian countries) is gift a timepiece (a clock or watch) - that means you want the person to run out of time (i.e., die), and that's not good for the "friendship" either! Hehe...
This is more of a Chinese quirk that plays on the language. Remember that Chinese is tone-based, and giving a clock is known as 送钟, which has the exact pronunciation as 送终, which is to pay one's last respects.