Do they scan the back of your licence? or check ID like at a bar for age?

Yes they scan your ID at the door and then they check your ID again at the counter when you go to purchase.

Yes

They scan the back.

Scan

Yup....no entry when or purchases when systems are down

They scan your license they don't ask any questions you go in get what you want and that's it

Yes they do

Just wait until you turn 21 man