That stuff can happen at any mechanic, not just dealers. It all depends on the manager or the shop policies. Some are very honest, some do needless work to bring in some money. The most common one is the fuel system cleaning. Most cars wouldn't ever need that until at least 150K miles unless the gas was run til empty several times. A simple bottle of fuel cleaner every 30K miles or so with a fill-up should take care of it forever.
I had the opportunity to witness a muffler shop that was advertising a $9.99 oil change. I was in getting my car done and the shop manager told every single person that their fuel filters needed to be replaced. I asked him when he told me mine needed it as well how he could tell it needed to be replaced. He said because there was corrosion on the outside of it(it was an external filter). I then informed him that I'd replaced it not even three months before. Needless to say he was a little embarrassed. The next three people after me passed on the filter as well after overhearing our conversation.
