My concern with bike racks (my home town provides them by the bucketload) is that they are often taken up with old beater bikes. I don't want to lock an expensive bike to something when the person with the next bike is unlikely to take any great care of it.

It's also a problem when items that can be removed are prone to being stolen. Quite often in my area I see a bike locked to railings and after a few days it slowly gets stripped of its parts. Sometimes we see bikes with one wheel missing, with the seatpost missing etc. It may be the owner took the seatpost with them to prevent it being stolen (I've done that before) but when parking a bike and leaving it for any length of time means taking the lights, GPS, saddle bag, pump, bottles, seatpost etc that gets to be a royal PITA and still leaves bar ends, pedals etc vulnerable to theft.

On a positive note I've found many shops surprisingly tolerant of me just wheeling my bike right on in. That said as far as possible I do my shopping at the quietest times because I don't like crowds, so generally it's not like I'm wheeling a bike into a shop which has so many customers you can barely move in there.