On Digitrax systems, if you try to acquire a loco address that is already in use by another throttle, you will get a warning of that, but also a chance to "steal" that address. If you do steal it, then both throttles can control that address, at least for a while.
On NCE, I CAN use 2 throttles to control the same loco at the same time, without any "steal" like in Digitrax.
There is a kink of consist/MU addresses with WiFi throttles. WiFi throttles make consists in the throttle, rather than the command station. So only THAT WiFi throttle knows what is in ITS consist. The command stations think the addresses are not consisted/MUed, because the WiFi throttle is sending commands to both, individually.
In Digitax, I THINK the command station would see addresses in a WiFi consist as independent (not consisted in the command station), so it would let a second throttle steal a top or non-top loco, and that would probably then have both the WiFi throttle and the other throttle controlling the same loco.
So, I suggest that you experiment with the system you have to determine what it actually does when 2 throttles try to acquire the same address, and recognize that consists in WiFi throttles are not the same as consists in command stations (which are also not necessarily the same as consists using the NMRA CV19 protocol.)