Maybe if it were actually a rebadged Ford then you'd have something to worry about. No current Mazda products are rebadged Fords. Lately, Ford has actually been using Mazda and Volvo platforms to make Ford cars. Probably better that way.

The Mazda 6 is actually being used as the basis for a ton of upcoming Ford branded vehicles but the platform was originally designed by Mazda. The V6 engine it uses a Ford block with Mazda heads.

The Mazda 3 is built on the Ford global C1 "platform." I say platform in a loose sense of the word. It is used in the new Volvo S40/V50 and is going to be underneath the next-generation Focus. Only things like floor pans, suspensions, etc are shared. Each brand uses its own motors, body panels and interiors. The structure was designed by Volvo, the suspension was designed by Mazda.

The upcoming Ford Five Hundred/Mercury Montego sedans are based on a stretched version of the Volvo S80.

The upcoming Ford Freestyle crossover SUV thingie is based on the Volvo XC90.

Etcetera.