I have two Street Beats, one rigged with a G clip for horizontal 11 o'clock belt carry, the other for pocket carry. Installing the G clip tightened up the sheath secure enough for safe carry. The other sheath isn't real tight, but it's good enough for pocket carry.
Like Brummie said, drill a hole near the neck of the sheath and install a Chicago screw if you need it tighter. Several other kydex sheaths have this feature. No biggie.
I've got a small fixed blade fetish going on. My "beater" is an Izula rigged up with an Azwelke sheath and a G clip, similar to the rig for my Street Beat. If I got pants on I have one of the three. Of course, that's not counting whatever folder or other blade I happen to be fond of. Why just carry one?