My original binnacle mounted switch was a simple old-style Lewmar rocker. My wife placed a handheld VHF on it without thinking and of course the chain started running out. We were sailing about 10 knots and fortunately the anchor was secured by a small piece of line, or it would have deployed.

That incident caused me to get a recessed rocker that's surrounded by a little box, like the one in the image below, so you have to place your finger into the recessed area. The original didn't have the surround.... so I presume I wasn't the only one who had the issue.