"Magnetic Forces" can mean a lot of things.
Electric MOTORS all use "Magnetic Forces" to make them spin.
The 'People Mover' (now called TTA) is powered by LINEAR INDUCTION motion transformers (a sort of "flattened -out" motor.)
But the Tower of Terror does not use magnetism to make it "go" or "stop"... it uses industrial electric motors to control the elevators.
All of the coasters at WDW use friction breaking (not magnetic fields) to stop the vehicles.
The brakes are operated by electric 'solenoids' (again a kind of linear motor with a plunger effect) but not a very strong magnetic field is generated.
I'm not sure there are any strong magnetic fields that surround the GUESTS at WDW.
The LAUNCH system for Rock 'n' Roller Coaster uses a Linear Synchronous/Induction Motor.
It can produce a very power thrust, but I'm not sure how much of that magnetism can reach the passengers.
That situation was likely considered by the ride designers, but don't know who could answer that one for sure.