Is there a problem in using rare earth magnets to secure parts for measurement that I should be aware of, especially with regard to affecting the force module or the head?

We are measuring  complex shaped thin walled plastic components and in two cases I cannot clamp the part onto the standoffs with out distorting the part.  I have some rare earth button magnets which I can place into the component above the standoffs and they hold really well.  While I know that you can buy magnetic standoffs for holding steel parts, these rare earth magnets are powerful and since the component is plastic they don't close the magnetic field like a metal part would.

Having said all of this, I won't be going really near the magnets with the stylus and staying at least 30 mm away.