Now, now let's not go all doom and gloom now, right?
This could work, with limits. Like I said, it can be coded into FLHook so you're only allowed to multibox if all your ships from the same IP have the module equipped. It could be logged on every docking / undocking so you could get banned fairly easily, just by going through the logs. The module could have a high price (CAUVIII tier) and require sufficient RP to acquire, and additionally be limited to specific ship classes (fighters, carriers, maybe freighters - not a lot of difference between multiboxing 2 freighters and simply using a bigger transport ???).
By doing this you basically eliminate around 90 % of would be casual exploiters (number pulled out of donkey's rear, but I believe it being a correct estimate). The rest can be dealt with just like now, with manual reports and bans.
Done this way, literally nothing would change, economy-wise (except there being an additional money sink), and yet it would also change so much by bringing a (frankly said, pretty obscure) option to the game that is similar to more mod(d)er(n) alternatives (hello, X series, or even Star Citizen).