I guess there are different definitions of what a spoiler is. To me, if you tell me I can unlock something, I don't consider that a spoiler. I still have to go figure out how to do it. But if you tell me
how to do it, then, yeah that's a spoiler, IMO.
Gamespot had an article about unlocking Indiana Jones and Han Solo a couple of weeks ago. They didn't say how to do it, but they made it pretty obvious that it could be done. I just figured most everybody knew about it.
I sure haven't run across it yet, so nothing is spoiled for me.