I have some Diamonique pieces I wear when traveling. They're fun and they look great. Although I haven't bought any new pieces in at least ten years, so not sure of the quality these days.
Do they still offer the lifetime warranty? Years ago I had a Diamonique ring in which the main stone clouded up. I called QVC. They said they would first have to do a search of their microfilm order archive for my original ordering info, and if they replaced it they would replace it with a ring currently in stock. Since the ring had a lot of gold, and there wasn't anything currently in stock that was similar, I said no. I figured out that I could have replaced the stone with a stock stone from WinkCZ for less money and hassle.
I have had jewelry stolen from my purse and hotel room while traveling, so I've learned my lesson. When you're traveling you're in a new place and out of your usual routine so it's easy to leave things behind on counters and tables. I never travel with anything that would bum me out if it were lost. I say, OP, that if you want to buy fun, fake jewelry for travel, go for it. But I wouldn't spend more than $100 on a CZ piece, if that. And I wouldn't buy anything incredibly flashy because you don't want potential thieves assuming it's real.