If someone is motivated to secretly or inappropriately film, they will do so with whatever device they have. Having these glasses doesn’t tell you anything more about whether they’re that kind of person than the colour of their shirt.
Whether you will notice is entirely context and situation dependent. In some cases the glasses would be hard to notice, in others the use of a phone would be hard to notice.
So while your perspective that people who want to secretly film stuff should be unwelcome is quite reasonable, the test you apply to detect it is misdirected.