I think I’ve done this a couple of times when in a rush but not many at all.
The main thing is I always end up pulling the wrong card out no matter how organised I try to be with my wallet. This is because when they’re in there, the ‘joint account’ words are not visible.
Kind of like when you try and put a USB stick into a computer. Guaranteed, no matter how hard you try you’ll never get it right the first time 
So while it isn’t a payment issue, it would be nice to have a more obvious difference between the two and the only thing I can think of is colour 