view once is not fully safe if they are determined to capture the image they will.
If anything, view once just makes the recipient of the image more likely to want to save it in my experience.
Video calls, voice calls and even in-person interactions can of course also be covertly recorded.
And banking records aren't the only way to find out your real name - it can easily be glimpsed on any debit or credit or business cards (including name of your employer) in your wallet.
So if you are paranoid about blackmail, use AI-generated or stolen photos, limit all electronic communications, never leave your wallet unattended, never fall asleep in the presence of an SB and consider wearing a disguise to meets
Being serious though, everyone has to manage their own risk but unless you are a politician or pro athlete or the like, I wouldn't get carried away. From what SBs tell me, a majority of guys on Seeking are married.
