I've encountered that twice. One was a young girl I insta-buddied with. I forget how I communicated the issue, but she was cooperative enough to hold still while I got it squared away. IIRC, it was her mom who surfaced with mask lines that looked like she'd have them the rest of her life, and didn't know why. Her strap wasn't too tight. She apparently did the entire dive without equalizing her mask,
The other loose tank was while snorkeling near Eden Rock in Grand Cayman. I saw what was apparently a DM or instructor in front of 2 presumably new divers at about 30'. Maybe that DM will post in the "most surprised" thread about the time he was tooling along and a snorkeler tapped him on the shoulder to point out the problem with the diver behind him.
We may have seen different marketing info. Working hard to not be cynical about their claim that "The main obstacle to snorkelling (sic) is the difficulty in breathing underwater with a snorkel", I think they may actually believe they've come up with a great improvement on the traditional mask and snorkel. Of course with the video showing newbies talking about their difficulties they're clearly targeting the new and clueless as a prime marketplace.
In principal some of it sounds good, but there's no way to equalize unless you can do it without pinching your nose. I'm sure that means their target demographic can't equalize in it, but I'm equally sure they won't need to. On the upside, that should mitigate the possible issues with getting it back on, since the people using it are almost certainly going to be right at the surface. And probably wearing a snorkel vest or hanging onto a pool noodle.
