Eric there are several important disadvantages to using back button focus... First let me preface my inferences here with the fact that I use BBF exclusively on location and when shooting events. It's advantages have already been thoroughly address in the thread and they indeed are rather significant to say the least! My shooting style is heavily reliant on BBF especially on location and at events.

However much of my revenue stream comes from studio assignments and here BBF can be a major disadvantage for my visual statement which is heavy based on low key scenarios. My studio is entirely flat black with no windows... All illumination is from modeling lamps which are configured to track with their respected output levels so that I can visually evaluate their influence on compositional elements. These modeling lamps are 150 watts at full power which rarely is reached even with my key light. So yes critical focus in such low ambient can be and is oft a challenge thus I will fall back on Single Servo rather than Continuous Servo on my Nikon bodies in order to obtain a conformation "beep" when the AF system has "lock". Since BBF requires Continuous Servo to function I have to switch it off...

A second very critical issue is I oft will use my D610 rather than my D3x in the studio... The D610 is literally blind as a proverbial bat and struggles to "lock" focus without it's Auto Assist Illuminator. Which obviously is disabled in Continuous Servo. Many of Nikon's pro-sumer bodies rely on their Auto Assist Illuminator without which will struggle in extremely low ambient. BTW: Your D500 does not have an Auto Assist Illuminator most likely because it has excellent low light focusing sensitivity. That said I don't use crop bodies for studio work, nor do my competitors... there are compelling reasons why but that's another issue entirely and unlikely germane to this thread...

Eric I'm certain others here on UHH may not find these limitations relevant but since you asked I wanted you to be aware that as with most aspects of photography so much depends on the needs of your clients especially if you are shooting commercially. Thus the concept of a signal solution is rarely germane in our craft... Hope this makes sense...

Final thoughts? Eric I highly recommend you try BBF in as it's advantages are so significant that your ability to shoot effectively in various challenging situations will likely be compromised without same...

Hope this helps and I wish you well on your journey Eric...

I shoot birds in flight, ALL THE TIME, EVERY DAY, SEVEN DAYS A WEEK. I have unscientific proof that the regular shutter button located on top of the camera (that Nikon and Canon, and Sony, and many others have determined the best place for it, other wise they would have but it on the back of the camera) has given me a 95-98% keep rate. I believe that is good enough, yes, I shoot with the best action camera in current production, the D500. I use that back button focus for changing my metering priority, which, for birds in flight, is more important to me than using it to fire my camera.