Disney Store is getting crazy on their processes! I go to my local DS and request Silver Hot Rod Lightning McQueen. They tell me that they have him, but he is not "Released" until the 8th of August! I explain that he is available online and they tell me that the online release date is different than in stores. What is that about???? This is the first time they have pulled this stunt. I wish I had contacts higher than the store managers to express my frustration.
I went to my Disney Store this morning to get the Silver Chase McQueen also. He was not out yet. That's not unusual, they hardly ever put out the Cars on time. Anyway, they were short handed and quite busy so one of the clerks went back to get me a couple. Last week I was told that today was the release date. I didn't bother asking today since I was able to get them.
To answer your question, yes it has happened to me in the past. A Car was online but they would not let me buy it even though it was in the stock room.