Let's see.
- A decent dedicated server with a 1Gbps connection for about £50 a month. This can be the "games server". Buy 2 or 3 for redundancy.
- A couple of hundred lines of code to provide 'telemetry' (as the devs like to call it) in combat
- Let the telemetry ping the games server every 5 seconds with data, call it a arbitrary 500 byte message
- Even with all 300K players online, in combat, the server could deal with that trivially.
You then have a method (and valuable data) to evolve the game mechanics.
It's hardly "hundreds and thousands of dollars", is it. The main cost would be the programmer time and it wouldn't be a huge amount of man hours.
So, as the holy hand grenade of Antioch goes, you're "right off".
You really have no idea how online games work do you?