I'd agree with the comments in this thread, that while it isn't always 'bad', it far too often is.
Viper, I'd prob re-list and just be open with the number plate, and if it is your car, remove the bit about selling it for a friend as that will understandably raise suspicion. I'd also personally not buy from someone who is not happy for me to view at their house (made that mistake once, bought a car from someone at a services - at the time I thought he was doing me a favour by cutting some time off my journey, but it was the worst car I have ever owned and the last French car I ever buy!!)