Full lockout on bench with hypermobile elbow joints?

[Peter Bex]

My wife has what looks like hypermobility in her elbow joint. See this picture where I asked her to extend her arms "straight ahead":

ima_4dd33fa.jpg

She says people always tell her it looks a bit freakish/scary, but to her it feels normal. I'm a bit concerned about benching though.
When she goes to what feels like full lockout, I imagine her bones are at a bit of an angle (it's hard to see from the outside exactly where the bones are of course).

For safety, we are supposed to completely lock out the bar as it travels above the face so that it is resting on the bones. But doesn't this presume the bones are "stacked" straight down?
I imagine having the bones at an angle would create a less solid base, which is more likely to buckle at really heavy weights.

Now, while locked out in the bench, it doesn't look as scary:

ima_3d39b82.jpg

But I'd still be interested in a definitive answer. Should people with hypermobile elbows avoid fully locked out elbows, or do the muscles around the joint strengthen enough for it not to matter?

[Mark Rippetoe]

She needs to learn to lock out her elbows in normal anatomical extension. It won't be an issue for while, but she can start learning this now.