yes, i reckon some do...maybe not all...
either because they think you're gonna bargain it down, or because they hope someone will just walk off the street and pay the sticker price. They'll always try to get the highest price they can!
i'd offer less and walk away, leave your phone number with them. If they're keen to make a sale they'll ring, or you can ring them back to see what's going on after a few days, if they've had no other offers they might be keen to bargain with you..