Thank you so much for your insight and information, amal!
With the minimal monetary investment involved with your xBT chip, I may order one and see what the feeders think about it. I am sure I could obtain a pet microchip, but I worry too much about something that was intended to be injected into a being that is “just an animal.”
I do understand the risk of injecting any foreign object into my body, and that this chip has not been tested or certified by any government regulatory agency for implantation or use inside the human body. 
That being said, the testing of the products on your site gives me enough comfort to give it a whirl, if the bowls cooperate. My only hesitation is the BioBond cap on the cBT…but I’m sure we can still get it out of there without too much trouble if we need to. For a pet microchip, I’ll probably revisit the jewelry idea. I’m actually reconsidering the regular old pet microchip our kitten is getting next week. If mine works with the feeders, I might just order one for him, too!
And the bowls do have a button that is easily accessible, but trying to feed three cats three different types of food at the same time (without any of them snatching the others’) is so hard to do with just two hands! These feeders have been a lifesaver (literally!), and I will probably always use them. I’ve been keeping an extra tag in my hand when I feed them, but this would be so much easier if it works! So this isn’t TOTALLY a crazy cat lady idea…right?