Why would AC or DC be a limiting factor? It's the RMS value of the current that will cause heating of the contacts. Could it be to do with the arc forming when the plug is withdrawn from a live socket?
In any case, using a domestic mains connector on DC is bad and potentially dangerous practice. From what I'm beginning to suspect, it seems to be only in this part of the world where there is an official low voltage DC plug and socket; ie the T configuration Clipsal 402/32, yet I am still horrified at the amount of 240V connectors being used for solar installations, boats, caravans, speaker connectors etc.
