Fortification is one aspect to this- much more so for an inbound power (where the capital is a bottleneck) but in the rare times a power preps or expands you have situations where you know pledges will be- as the cycle goes on and the inevitable rush at the end.To expand upon what @Rubbernuke is saying, currently there's a teeny tiny chance I might be interdicted in Open if I want to make a fortification run in an iCutter between Cubeo and, say, Runapa. Because of this, I might equip my ship in such a way that it'll take two extra jumps to get there, and I also might bring along 8% less cargo, compared to what I might do in Solo.
This could result in an astonishing 16% fewer fortification cargo units being delivered per hour. Which, in this case, amounts to an extra 15 minutes to fully fortify that particular system. Mostly thanks to needing to make ten runs, irregardless of cargo capacity.Keep in mind, this system is one of the worst to fortify that I know of for Aisling Duval, being both distant from Cubeo and a relatively long Supercruise run.
Or, given that this is version 1 we're talking about, I could simply trust my own skills, and how unlikely the matchmaking system is going to instance me with a hostile player, and simply do the run in Open the same way I'd do run the run in Solo, and get the same results. Especially since it would take about six players doing nothing but flying opposition for nearly three hours to maximize the chance of intercepting me. And that chance is drastically lower if I play outside of my local prime time.
And since I'm pledged for an outbound fortification power, at the beginning of the cycle, they'd also have to cover 72 other systems, each with several stations between them.
Which is why Rubbernuke is advocating for having NPCs provide opposition towards fortification instead of players.
This was why Sandro wanted unlocked UM and fortification, in that you could keep pressure on a system and people would have to defend it- unlike now where (unless maths is at work) once a place is fortified that effort is wasted.