Easy outs (proprietary extractors in England) or special bits are expensive and if an easy out snaps you have a worse problem.

If you have a drill press and the screw is counter sunk drill into the screw head along the axis of the screw until the counter sink can be snapped off. Use a depth collar on the drill to not counter sink (drill into) the plate.

Then when you remove the registration plate you can file a screw driver slot in the residue of the screw and unscrew. It should not be tight with out the friction of the counter sunk screw head.

[not for clumsy] if it is tight and you suspect galling before you damage the head seat a screw driver in the screw and tap the end of the driver with a light hammer this will break some of the adhesion[/not for clumsy]

Mine were not that tight...

Zorro