How irresponsible of the vet. I take it he/she was quite young? I bet he failed THAT question in the exam ;)
I'd get in touch with the vet concerned and give him/her a piece of my mind

My dogs are now fully recovered (thankfully) from contacting KC at Blackpool Ch show. We only walked past (about 3') from a dog that might have coughed and ended up with 3 very sick dogs :( Mine were kept in until they had stopped coughing, and were then only taken on short walks for a couple of weeks. Drove me mad. :D They couldn't understand why we had to turn back too soon :)