Eventually, many will aspire to fly the big ships. Clippers, Federal Dropships, Anacondas and other to-be-introduced large ships will keenly sought by pirates and - unfortunately - murderers. At least those that aren't seeking a challenge. By limiting docking pads to the medium variety at outposts, these folks will be forced to stay in anarchy space OR fly into non-anarchy space ports with scans/security to restock/outfit. This obviously becomes a risky proposition in a 100M+ credit ship. And, it's one with diminishing returns as those folks will need to pirate a LOT of little guys to make that profession worthwhile - IF they choose to fly big ships. So, by making the risks and economics the way they are, pirates will either be forced/encouraged to stay in anarchy space for their piracy/murderous effort or play in smaller/cheaper ships. Pretty clever, I think.