You can watch the numerous replays of the chokeslam bump beginning at 12:50
Judging by how the bump was executed, I believe the chokeslam through the cage was completely intentional.
A normal chokeslam would finish with Taker's opponent bumping right alongside and almost underneath Taker. The chokeslam to Foley through the cage is quite different.
Watch the way Taker pushes Foley forward and away from himself (Taker) with the chokeslam, seemingly to ensure Foley bumped on the section that Taker was not standing on, to ensure Taker would not go through the cage as well. Also notice that Foley's feet are on the rail as he leaves his feet for the bump, probably to further ensure he bumped on the section Taker was not standing on. Perhaps that particular section he went through was even gimmicked to give way exactly as it did, so that perhaps that had to be the section he took the chokeslam bump on.
Of course this conflicts with Foley's account that, sure, the bump off the cage through the announce table was planned, but the chokeslam through the cage to the ring was totally unexpected.