Double First Base (ASA Rules)

[Little Jimmy]

Irish Mafia sites ASA 8-2-M-3 where defense or batter-runner may use either bag on a play from the foul side. Good enough. But doesn't that have the potential to cause a collision as opposed to avoiding one? Saw a similar play as the one Toon Army described. Wide throw to first, F3 gets ball and dives prone to white portion of bag essentially leaving batter-runner nowhere to go. Plate ump rules out because she left runner no piece of the bag to touch. I was a spectator but it seemed like the right call at the time. So am I to assume that F3 can indeed go to white bag from foul territory even though it leaves runner no real space to go?