Dump Station Etiquette???

If there is even one waiting I go with no rinse. If I am rinsing and someone pulls up I am done.

If you ever get a full hookup site you can rinse to your heart's content.
Every 3rd to 10th dump is fine. It is just a holding tank.

bgum answered clearly, to the point, and most important, briefly!

After dumping add some water back into black tank so bottom stays wet.
That way poop doesn't stick to bottom of tank

Either via the Black Tank Flush after rinsing IF dump line is very very short
Otherwise flush couple of full toilet bowls ----use the on board pump

“Are you allowed to rinse the tank after emptying when you are at the station or is that frowned upon?“

With no one behind you, rinse to your heart’s content. However, rinsing is mostly unnecessary if your tank was full or nearly so. If possible fill the tank before dumping.

If there is no line you can rinse. Otherwise dump and go. If you are using enough water you don't need to rinse every time anyway.

Yep, long line behind, dump and go. If there is noone then get out the hose and shove it down the toilet till half full and dump again. Another quick rinse if you don't have a sani wash is to lift up the sewer hose and put water in it for awhile and then lower it down to the dump hole. If there is a big line I dump and pull out and stop at a wide spot and add a couple gallons or until I get tired of hold the flush valve on the toilet so it will slosh around on the way home. It will get the toilet paper off the sensors and dump when you can or on the next trip first thing when checking in.

Rinse after dump. Rinse less the longer the line. Full rinse with no line.

This will surely garner pages of opinions and, umm, uhh, discussion, but you can bank on not upsetting everyone in line behind you if you get in and out quickly.

Since you are unfamiliar with RV holding tanks, first know that you in no way need to rinse the tank every dump. If there's people behind you, dump the black, dump the gray, get out out of the way.
If you're not holding anyone up, feel free to rinse and clean until you're tired of doing it.

FWIW, I generally do a little "clean" of the tank(s) maybe once a year or every other year (probably use the camper a half dozen times a year). And my cleaning consists of filling tank part ways with soap and water, drive a ways, dump, done.