Any time someone has their phone out, whether it appears they are talking on it or just txt'ing, they could be recording. It would be trivial for me to fake a common phone task, but actually be recording video of anything in the bar. Yet, no one confronts me just because I have my phone out. There really is no rational reason for people to treat those with Glass any differently than anyone who doesn't have their phone in their pocket.
"Necessity is the mother of invention" is a silly proverb. "Necessity is the mother of futile dodges" is much nearer the truth. -- Alfred North Whitehead