My stance on it is that if the person isn't claiming the art is actually theirs then I don't really care. RP isn't for profit and I get people want to have an image to be a bit more eyecatching than text. I would prefer that they link back to the original, as it helps give me exposure. Equal exchange. After all, being an artist isn't free. It costs a lot of money and time and work ethic to actually be decent. 

What would be more helpful is if people commissioned artists more to draw their OCs, because most of the time that gives you rights to use the image. Things like simple headshots tend to be cheap, so if you're the kind of person who reuses their OCs or adapts them then this is ideal. Some people will even do expression sets if you ask. I for one love OC commissions because doing fanart is boring af to me. 

Also, on fanart. If I'm being quite frank I don't give a damn if people use my fanart for rp. Even without sourcing me fanart tends to get attention and if someone really likes my fanart they will find me. People can be [i]obsessed[/i] with their favorite series.