I am about to run a game for two players. The decision is made to use randomly generated stats using 4d6 drop lowest, arrange as desired. To save time, I generate the stats. Th first set is all 14's or higher. The second set is all 12's or lower. I flip a coin to see which player gets which set. Is that fair?
What if I had decided before I generated the stats, "these are Tracy's stats" and then, "these are Terry's stats": would that be any less fair?
Statistically speaking, the methods are identical and a they are statistically equivalent to letting each player generate their own stats.
To say the resulting game experience will be equitable for both players is to misunderstand the definition.
It may be statistically equivalent and also equitable (equitable: "fair and impartial"; fair, just, impartial, even-handed, unbiased, unprejudiced, egalitarian) by some definitions of "fair" including the one I'd use. That doesn't make it a good idea. Mathematically, rolling saving throws
for the players is equivalent to letting them roll their own, but I don't think many players like having the DM roll their saves for them. It feels like stepping on the player's toes, and especially in this case, the players are likely IMO to feel that the experience is a bit cheapened by you having rolled these stats for them. But maybe not--if they
asked you to roll their stats for them (as I have done with some DMs) to remove any possible suspicions of cheating, then the players would be fine with it. I would, anyway, and if I got the 12 and under set I'd play either a Moon Druid or a Sorlock, because either one can be fun with low initial stats.
(
Cha 9 for a warlock would be pushing it--I have a Cha 9 sorcerer in my current game, now Cha 11 due to ASI, and while he is playable, his niche is narrower than it could be with better stats. He throws a lot of Magic Missiles for example because Cha doesn't affect them. If all stats were 9 and under I would definitely make a Moon Druid instead of a Sorlock because Cha 9 goes past my personal boundaries of where fun is.)