I haven’t been able to get a straight answer on this but is TCAS working with multiplayer and AI/Injected traffic? This is for GNS530/G1000/G3000 airplanes in the sim.
In Multiplayer, does the transponder setting impact visibility in multiplayer?
I did a multiplayer flight today and we were not seeing each other on the traffic map.
Works for me when doing multiplayer group flights. They even change colour and give traffic call-outs. Next time you try also have a look at the tool bar map to see if you see aircraft symbols there also.
Yes but you have to turn it on. Each Garmin has their respective traffic page. You’ll need to toggle to this page then turn on traffic / ADS-B. Much like the weather radar pages if you’ve played with those…
My burning curiosity is do the other players need to have their transponder on. 
They show up regardless. The sim acts as if they have theirs on so you can see other aircraft.
Actually a little disappointing!
I’ve only recently turned off the copilot assistance on the radios.
It may just be there usually the reasons to turn the transponder off are not for good reasons. Although not required in class G.
I’ll have to test out if the AI system notices the transponder.