Fleeing combat and landing on a station is not a violation of the rules, no matter what class of ship you're flying.
If you land on a station, restock on bots/batts, then reengage, that is a violation of the rules, even if you are a transport.
Liners are transports. They have their own class - Liners, but that class is a transport under the rules. Meaning it's a trade ship that is subject to the transport rules. For IDs though, you cannot fly a Liner unless your ID says it can fly liners.