I <3 Marvis. :wub: It's an Italian brand, and I've been using it for years and never noticed a safety seal (the full size is sealed in a cardboard box.) I think it's safe (and wonderful) to use.
To be honest, I think Glossybox has been in a bit of financial trouble over the last year or so. One of their co-founders left the company late last year, and I believe they had to pull out of a bunch of countries because they weren't profitable. I don't know how that relates to their profitability in the U.S. market, though. I haven't really noticed a degradation in product quality since I've been subscribed per se, but every once in a while they include what seems like leftovers or brands that don't really fit with their image and it makes me wonder. It seems like one month I get a fantastic box (hi Bergdorf Goodman and Net-A-Porter) and the next month it's not so great. Sometimes the brands are super high end like La Prairie and Sisely and Beauty Blender, and then the next month you'll get Be a Bombshell and Aqua Spa (which can be purchased at Walmart) or leftover Ciate colors from a few seasons back that weren't selling. Then the next month, it's Chantecaille and Sulwhasoo...I'm not sure what the problem is.
http://venturevillage.eu/glossybox