Originally Posted by stut
I'm slightly confused. In older hotels with 'traditional' lock and key, yes, they generally request that you leave the key with them when you go out, because they're a pain to replace.
But the key cards? In 3 years of pretty much weekly travel to about 15 different European countries, I have never seen this.
It happened to me earlier this year in Paris. I stayed in a small hotel that used keycards, but they did ask me to leave the card at the front desk whenever I left the hotel.