Electromagnetic Relay versus G-Force
An appropriate relay for your application will have a specification for shock and vibration reliability. For example, here's the spec from a particular automotive-rated relay I found:



Notice that the spec doesn't promise absolutely no change in contact status, only that (per note 7) it won't make or break contact for more than 10 us at a time due to the specified shock and vibration. So you may need to design your circuit to allow for brief relay faults.

Given these issues, it may be easier to design with a solid state part than with a relay.