Hopefully you weren't hurt in this incident.
When you say "lock up", do you mean that the steering wheel "locked up" as in "couldn't turn", or the power assist failed, making the steering wheel very difficult (and maybe impossible, for someone with limited upper body strength) to turn? Those are two very decidedly different failure modes.
No, I've not had either happen, although I'm still intrigued as to what the failure modes for the electrically-assisted power steering on my Ion might be. The common catastrophic failure mode for hydraulically assisted power steering is well known--drive belt snaps, presto, no more power assist, it takes a lot more effort to steer but you can do it.