So it is a do nothing. I have not been very impressed with Wahoo's support, and if they recommend doing that, particularly in light of Iride01's claim that the battery will not make contact, I have even less.
Iride01's claim sounds like it is probably true. Many of those coin cell contacts grip the side and contact the top. On a coin cell like the ones in the Wahoo, if they don't contact top and bottom reversing the battery is a do nothing. Note that I just had my car's fob apart to change the coin cell, and it has side grippers along with top and bottom contacts. I am sure that fob costs quite a bit more to build than a Wahoo sensor and, since mine tends to go through the washing machine every couple of months, it is a more rugged design.
Yes, capacitance is close enough for government work, The charge stored in capacitors needs to dissipate to completely shut down the electronics. I was involved in developing a product that kept enough charge in a capacitor to keep a real time clock running for a week, so that we could loose the battery and when it was replaced, we would know the date and time.
As a side note, here is an article which describes a simple reverse polarity protection circuit:
https://components101.com/articles/d...ity-protection