47k is not high by most standards - these guys with super-low miles are just being smug - but it won't last if they use them as itsky suggests!
Over here around 40k is thought of as relatively low - certainly below average.
The most expensive Crossfire for sale in the UK at the moment (AFAIK) is an SRT coupe for for £11k with only 12k miles - that's really low - amazing no-one's bought it yet. Really low mileages are becoming quite scarce now - even in our little country! There are a couple of NAs with 14k miles @ £8k (been for sale for ages) and a few with around 20k but's that about it for really low milers. A few more at 30-50k but the vast majority are well over 50k. Shows they've been enjoyed I guess which is what counts. It seems they're cheap to buy compared to the US but running costs are high - premium is around £1.50/litre = about $8.77/US Gallon!! But that's a rant for another thread!