I'd say it's easier to covertly film someone with a smartphone than with glasses that have a lightup LED. With the smartphone you can just angle it to look as if you're casually holding it or using it normally.
This complaint is about a different law (§ 8 TDDDG), that explicitly forbids selling and owning devices that are designed as every-day objects and that can record sound and/or video and that.
So you film the ground?