I think it the ones who wish to gain favour in x,y,z, systems... Sell some here etc.That's really my question too. People are somehow making a concerted effort to go to Kill Land Supreme to sell their data, rather than stopping at, like LHS 374392 (dunno if that's a real system but you get the point) and dropping it off to the local pack of random democrats.
I've often selected stations (that aren't SD) to sell data where being allied would be 'useful' - but never one in a hotspot!