Government forcing you to carry ID

Forcing you to carry identification you when out and about allows police and ruling powers to throw you in jail if you dared to forget your ID, or throw you in jail and claim you had no ID. There are a number of things every tyrannical government does, one is they force people to carry ID with them all the time, another is they disarm the people (but that is a discussion for another time). My identity is no one's business but my own and anyone whom I choose to share it with.

The Federal Government has exactly 3 times when they are allowed to force you to produce identification: Entering or leaving the country at Customs, when arrested by Federal officers, and when conducting a transaction with them (taxes, welfare, voting, etc, etc).

You know what would be more secure and more efficient than ID cards?

Social Security number tattoos.  They could put one on your left forearm.  And maybe a barcode on the back of your neck, readable by electronic scanner.

What?  You don't like the idea?  What are you, some kind of nut?  Don't you trust the government?  Are you crazy?