At least not in Game Master. When you add a new respawn point, or spawn an ordnance, the game automatically informs players of it through a radio message.
This is annoying, especially the artillery part.
I was making a mission where players were in a base, and I wanted a sudden surprise artillery attack (Without killing them), but couldn't as I knew it would automatically tell them it was coming.
This is intentional - players are warned about incoming strike when they're less than 100m from the ordnance module, so they at least have some time to react. Without it, Zeus would have too much power. If you want silent strikes, spawn ordnance modules further away.
As for respawn, it's also as designed. Players have right to know when new respawn point is available.
I know it's intentional, and it makes sense for all the game types, except Game Master.
Otherwise, the lightning should have a warning too...
Isn't that the point of Game Master?
"Nothing in this scenario is predetermined. No playthrough is the same. EVERY STORY, LOCATION AND EXPERIENCE IS INVENTED AND CONTROLLED BY THE GAME MASTER. By Zeus."