@PinheadLarry - As for how to spot fakes yourself, it's pretty easy for some, but VERY hard for others. It comes down to comparing usually, or knowing some of the easy to spot 'tells' of common scrapper (or fake) pins. For example the pins that do have a mickey on the back will have it going all the way off the edge, while fakes will often have a border from an incomplete back-stamping. Misspelled words, missing years, wrong colors, can all happen as production errors, but are more common in fakes.
There are also some pins that have been faked SO frequently that people know to keep an eye out or simply avoid trading for them altogether. The newest Disney pins (sold at the parks or on shopDisney) have a little Mickey head made of cubic zirconia sometimes called 'diamondback' pins, these have not yet been faked so I believe they are always considered a 'safe' trade. Again, it's a lot of looking, comparing, and asking,
I honestly still have a really hard time being 100% on a fake or not even after twenty years. If you poke around the forums you'll probably find people who have posted pictures of their scrappers and what to look out for.
If you're collecting something specific, look it up and see if it's a pin known to have fakes and what to look for.
Check out some of
these threads to help you compare and figure out some of the 'tells' for fakes.
Hope that helps a little!