You can choose any bindingphrase you want. Make it an combination of a few characters and numbers. I cant prove it mathematically
but the chances of someone at the same event at the same time you are on track has to have the same bindingphrase is negligible.
Every ELRS Reciever can create an own wifi network, you can even connect to that with every smartphone via the browser and change the settings. The wifi network won't appear if the transmitter connects to the reciever before a set time has passed. So no one can alter your settings of your reciever while driving.
There is also a Modelmatch option you can turn on in the ELRS Menu of the radio. If this option is active the matched reciever will only work if the corresponding model is selected in the radio. Even when there are more than one active recievers with the same bindingphrase in range.
ELRS has a learning curve for sure but not too bad especially if the transmission protocol is proven reliable and the recievers are between 15 - 20 bucks.
In comparison to the different sanwa protocols available FH3T, FH4T, FH5 the different servo modes SHR, SSR which you can only set while binding the reciever and won't change every time so you have to rebind the reciever a few times.
Which Sanwa Radio supports which protocol and can bind to which reciever .... i think you'll get my point.
With ELRS every reciever works with every transmitter, the only requirement is they need to be on the same major firmware version. And every reciever / transmitter is updatable. (also over the WebGUI you can enter when connecting to the wifi network the reciever provides, the same applies to every transmitter)