I can't speak for those in Denmark, but I consider a pony critical to my diving as a solo diver. True, here in SoCal you don't see them all that often but most of the time you do it is a solo diver. I consider a pony very wise insurance under those conditions, but do not consider it as part of my usable gas on a dive... only in unexpected emergencies (such as the obstructed dip tube I experienced at 75-80 ft shutting of all air flow from the main tank).