It makes sense to keep all the operations similar. Also, in the true sense of REST there is no resource actually being deleted. The association of the device to the consumer is removed, but that association never was a resource, i.e. there was no URL to a resource representing the association in the first place.

Furthermore, the DE currently implements this as POST. DELETE fails, so all working implementations (client and server) must be using POST.

Proposal for resolution: Change the DELETE to POST.