[otherguy]

A reed switch is still a mechanical device.
My guess is that a magnetic field overcomes the force applied by some spring steel or something?

I'll walk through my rational, but state up front that I have very little experience with reed switches. I could be writing them off prematurely.

While the reed switch is non-contacting, it would still be susceptible to conditions that would cause the reed to move when the actual physical component it is mounted to has not (i'm thinking shock event).

The hall effect sensor on the other hand has no moving parts (it may be more accurate to say the MEMS components that do move have such little mass that they won't accelerate significantly do to shock). So the only time they should indicate a state change is when the magnet (and the component its connected to) actually moves away from the sensor.

That said... looking through digikey, there are some pretty tiny surface mount reed switches. It might be a viable option. They are in the same price range as the hall effect sensors I used.

At the end of the day the hall effect or reed switch is just another tool in the toolbox for us. It's not going to be the end-all sensor. I like to have options on hand so that if we have ideas we can prove them out quickly. Hopefully they end up on the field, but if they don't it was a pretty small investment. I ordered electrical components off ebay, with the custom PCBs, these things come in at around $2.50 a board.