As a mainly trader player i can post some reasons :
If i fly my 5000 full of gold ore or something ( which i paid up to 20 m ) , i will naturally try to save cargo if i can , so i will accept reasonable money demand ( up to value of cargo on buy location , not selling price ) , and if i don't like pirate attitude , i will not give him maximum price , even at cost i loose all , i will rater return to starting point in some cases .
Also , i will pay higher price to lone wolfs they deserve reward for effort , i hate paying groups of line campers why simply sleeps near all trade lines in systems, and gathers when some of them see easy pray .
There is also some times , when i will simply not pay not even one credit . Like situation i was in Pennsylvania , i am in Liner parked 200 m from Erie docking ring , empty , just chating PM with friend , and some Outcast show up and demand 5 m , i mean , it was more ridiculous than real treat :
I say : "5 m for what ?"
He say : "to let you live"
I say : "good luck reaching me while i was here!"
He says : "i will not let you leave planet orbit then "
say : "i dint intend to leave anyway , i can sit here all day, how about you ( this hole time he tries to type and evade razors from patrols and bases lol) ? "
After some time he finally got it and leave . I will never pay single credit to players like that , who obviously want trouble in any situation , they don't have decadency to leave when they see someone is not in RP curently chating .
When i am in my Cloak liner , that is different story , i will use bribe only as last resort , i don't fly that flying brick liner for profit , it is to enjoy of feeling i was able to outsmart pirate/s and save passengers in "o how i love to stuck ship" if i can , if i cant , oh well , at least i tried and it was fun .