[Loic]

Last time I was there in Denmark I had to provide a CPR number to enable the SIM card. For the non-danish people the CPR number is basically your lifetime number for everything from social security, to tax, payroll, etc.

[Symbiote]

Perhaps if you want a contract, but it would be rather pointless requiring a CPR number, yet selling SIMs in the arrivals hall of Copenhagen Airport.