Age Verifications: where do you draw the line?

choose all that applies

boosts appreciated 

against with the idea in principle (no other options applies)
a self-certifying checkbox is okay
offline verification of ID document is okay (via reading chip or OCR)
Credit card verification is okay (if you have one you are >18)
Mobile operator verification is okay (if you have a contract you are >18)
First party online verification is okay (upload ID or photo to the website you are using)
Third party online verification is okay (upload ID or photo to another website)
other (write in)
Poll ends at .

@kuriko I said self-certification only but it really depends upon what you’re doing it for

fwiw the card networks are moving towards offering age verification for debit cards (your bank knows how old you are), which is an interesting development