Just something I have noticed is that the warp lines are off by default on the system map which makes it very difficult for new players to have any chance of knowing a warp is one way. I have asked on many servers what the rule is on leaving starting planets and generally they all say the same thing. You can leave your planet and come back but not your system. Yeah... that's not the case sometimes. So my suggestion is A) Make the warp arrows always on to help identify the single direction of the warp and B) have a dialogue box pop up for the first warp informing the player, this is a one way warp, you may not return. This is a courtesy and I am sure would go a long way to help limit new player frustration. Incase it is asked. This happened on the US Official server when I warped from Taldar to a neighboring planet in the same system. Still in the same system, just a different planet because Taldar is a dead moon and you kind of have to get off of it to do anything. Just now all my stuff is lost back there.
In the default game no warps are one way. For servers they should inform players of this through Discord, in-game messages, or the PDA. It's the server's responsibility if they are running custom content to properly configure it and communicate it to players (and likewise the players are responsible for reading the server information).
That is interesting that the default game does not have any one way warps. It is a fair statement to make however that probably over 90% of the current player base plays on modded servers. Even the majority of official servers run mods so exposure to the default is likely extremely limited. I agree though that it is the responsibility of the mod creators/server owners to clarify such things but as this observation occurred on an official server I felt posting it here on their forum was appropriate. Having the ability via the game to configure a warp to be one way my request would simply be that the client provides a simple dialogue box whenever a player initiates a warp that is set as one way. I feel it would be a great kindness.
It is not. Current player base may include thousands of players who run Steam offline and play unnoticed in singleplayer, and lots of others play coop with no modding. All statistics compiled in the past to see how many people were playing Empyrion could only account for a tiny percentage of all active players because of offline mode.