It may be.
My brother lives close to tram tracks and very often, the surge in electromagnetic radiation generated from the tram is enough to wake his computer, because it is interpreted as input from the mouse. Also, mice these days are a lot more sensitive, so they register even minute movements. Both can be the cause here.
I'd put the mouse in its cradle (if it has one) and see if your computer still wakes up from sleep. If it does, em interference may be the cause.