==================== RULE: None Obvious QUESTION: Within the server rules there is nothing mentioned specifically about any connection with player IDs and use of tech (4.4 comes close, but it appears to be PvP specific rather than governing what someone can use.)
I am assuming that power drain related to incompatible tech replaced the old rules regarding tech usage, so my question is really is that correct? Assuming that a player accepts the power drain penalty and whatever the RP consequences of their tech matchup are, is it fine rules-wise to mis-match ships and equipment without an SRP? (e.g. RPing a Rheinland Battleship captured by the LN in the previous war or a Bretonian privateer showing off captured Kusari/Gallic weapons. I would personally draw the line with Nomad stuff unless I had done considerable RP around it beforehand, but it's a possibility.)
In short, has tech compatibility power drain replaced ID tech restriction rules? ==================== ADMIN/MOD ANSWER:
The area is a grey one.
In short - yes, but with a large asterisk when it comes to technology you would physically not be able to obtain. In other words, an outcast ID with a Liberty Rogue ship will receive a modest powerplant nerf that acts as balance.
An outcast ID with a corsair ship - where it receives a 10% powerplant, however, should not be done.
A non-nomad ID using Nomad Lasers - should similarily not be done.
If it is impossible for you to obtain the items without assistance of another player or other such means - refrain from doing so.
In short, your specific example of a rheinland battleship being obtained by a LN - technically it would be allowed as you are able to dock on a base that sells it with a Navy ID as a neutral faction. However, if you were to try to obtain a Liberty Rogue ship, that would not be allowed. Common sense would be the best way to apply this approach. Similarly it should be noted that players should hold up a higher roleplay standard than the ''lol I stole it'' approach that has become one of Discovery's defining mockery/memes since the early 2010s.