I am yet to hear someone being sanctioned for making one RP demand, that can be fulfilled without getting blown up.
I often interrogated my targets and then asked for smaller credit demand than I would have originally. So far I was not sanctioned for that. Some members of my faction also demand to state something on system-wide channel. No frustration from that either.
And the fact that some players are not used to be asked to perform a task might do something with the fact most criminals only demand cargo or credits with little of intention to do anything more original. Or the fact that some traders are just dumb and have no idea what roleplay is.