A Korg Krome 61/73 review mentions that you can jam fingers between two keys because they are flat. I've had an opportunity to play some cheap keyboards with flat keys and this didn't happen to me.
For considering this issue while buying a new synth, I would like to know: which playing techniques are vulnerable to this happening? And is it truly a problem at all (i.e., can it really happen when you play the keyboard or is it just another negative remark in the overall negative review)?