This is where you're wrong. It wasn't a pricedrop, Futureshop decided themselves the game would be 70$ and used a placeholder price so that you could preorder.
The official price is 45$ and you preordered the game under the assumption that you would get a 30% discount if you did so on the game's price.
If you let it slide, nothing in the future would prevent FS/BB from raising their placeholder prices to 80$ and rip you off ou tof the promotion in the process.
Well it was a price drop in the sense that the price for the game dropped from their price. This happened last year to people with Tropical Freeze I believe, too. I'm pretty sure they put in the fine print that the deal won't adapt to lower prices in the future.
And as for them artificially pricing things at high placeholder prices, there are numerous reasons why that would never happen. Customers are dumb, but not so dumb as to let that slide.
I mean, in my mind I ordered a fuckton of games at E3, and ended up saving a fuckton of money in the process. None of us were contacting Amazon during E3 and letting them know when their system was clearly fucked up and giving us a wayyyyy better deal than we should have been getting. So who am I to get all pissy that a game dropped in price, to a price that I was already happy getting it at anyway? Who gives a shit? Not a priority, not worth the time to me. Some people though, have plenty of time, and if that's the case, then by all means call and get your $8 back. If the Mortal Kombat X i ordered at $48 drops to $29.99 before release, I'll be happy as a pig in shit! I was already happy paying the $48, but extra savings? Great! But I'm not going to get all pissy at Future Shop for not giving me an EXTRA ten dollars off!
It's life, you win some you lose some.