[nwh]

Gox mentions this on a number of occasions, not the least in 2011 when they detailed how their cold storage system worked with split keys.

[jonknee]

Gox also mentioned a lot of stuff before it went dark with everyone's coins. Something obviously went horribly different than planned.

[dsrguru]

In fairness, it's somewhat likely that everything went exactly as planned, at least for some of the people behind MtGox.