TL DR: It shouldn't be a concern whatsoever.
If the switch is like any other of this type, the idea is for the hood to come down and press down on it, and thus disconnecting the grounding source. In order to do this, it is mounted in an area, like the core support (cross piece where the radiator sits) where the hood can come in contact with it. You set the height of the switch (thus the threads and nuts associated with it in the body of the switch) so it will just contact the hood as it comes down. Other than the plunger, the switch itself doesn't move. This means when you set the switch in place, you can place it so the spade terminal doesn't come in contact with any other metal part of the car. And, if it suits you, you could also put some heat shrink or what have you over the area where the spade terminal is at, thus further preventing any grounding which may occur. If something did come in contact with the spade terminal, the worst which would happen is the light would come on.
As an alternative, most newer cars already have a switch under the hood which tells the driver if the hood is open prior to taking off (just like a door ajar or trunk lid open). If your vehicle is setup with this already, you could possibly tie into it to get a signal that the hood is open. It'd take extra wiring and configuring, plus you couldn't directly power your light through it as the plunger switch would, but it would do the same basic job and wouldn't entail placing another switch. Just a thought.
