I've heard of and installed both full spread glue down sheet vinyl and perimeter glue down sheet vinyl, but this is the first time I've heard of a glue-LESS sheet vinyl. What holds the flooring down?
I believe that if you cut the flooring to fit the room, it'd probably stay in place reasonably well without being glued down, especially if you nail any shoe moldings down through he flooring. But, if it wuz me, I'd be sure to caulk the joint between the baseboard or shoe molding all the way around the floor. I'm thinking that rain or melt water from snow could leak around the edge of the vinyl and get under it, and you'll end up with a purple/brown stain showing through your vinyl cuz of the mildew growing inside and under it.