Genuinely curious: what concrete negative consequences are there from appearing in the background of other people’s photos/videos, in a full face mask no less? Is he afraid that someone will be able to identify him as engaging in a hobby that some people might be judgmental about, e.g. a potential employer finding the footage and concluding “this guy spends lots of time and money playing a children’s game; he’s clear…
* Don't want to be ridiculed if you look silly (it is airsoft, after all)
* It's distracting to be videoed
* You have a stalker trying to find information about you
* Makes you feel pressure to put on make up and look "decent"
* Something you say might sound bad out of context and result in being ostracized or otherwise socially punished
* You might have a secret airsoft tactic or codes you don't want people to know about
* You don't want facial recognition trained on you
* You told someone you couldn't go to their party because you are sick and don't want to get caught lying
* etc etc
These aren't all huge issues, but they are reasonable.