No face, just mask recognition ? - I may like it, as here no person bothers to remind about it. But imagine.. "someone's mask slipped down his nose.. starting

No face, just mask recognition ? - I may like it, as here no person bothers to remind about it. But imagine.. "someone's mask slipped down his nose.. starting faces recognition in 3.. 2.. 1 second" I'm scared of using tube since some women cough straight on to my face and then just said "I have mask exemption", no apology - with no time for me to react, I could only tell her "I don't care about your exemption or which virus you don't have, just cover your mouth when you cough !" - I think is a cultural thing - here in London no one is doing any of this.