Surely the solution is to buy different collars rather than have the dogs loose with no ID at all though! Even dogs with the best recall can still panic and bolt. I'm wary enough about the idea of leaving dogs in the house without a collar incase they were to get loose but I'd never have them off-lead on purpose with no form of visible ID.

Lovely pics, they are all gorgeous

Don't like those collars though, the spikes are huge

Lovely dogs