I hate spotting rules.
Any rules that have visibility/spotting rules, we always throw that part out unless we're specifically playing a scenario where one side is concealed in their starting positions.
Striker ? Threw it out.
Command decision ? Thrown out.
Firefly ? Nope. Out.
This morning messing with Panzer War ? Get out of here.
Just about the sole exception is old school 40K with the "Hidden" rule, probably because its deterministic (Within your Initiative in inches, you see them).
To some extent, I agree with Ed's words in the original edition of "Nuts": If the player can see the models, then the player is going to react to them regardless of whether they are "spotted".
If you want hidden models, remove them from the board.
That's paraphrased but I am inclined to generally agree.
Additionally, I've found that a lot of players will laugh at missing multiple shots in a row, but missing a spotting check and being unable to shoot at all makes them rather grouchy.
What's your gaming confession?