Absolutely a DQ. It’s a general safety rule, it’s frequently a range safety rule and its organized competition safety rule (IDPA 2.14, USPSA 2.1.3).
You get someone running a 38 supercomp, 38 special, 357 mag, 9 major, 9 +P or even some hotter 9mm minor handloads and you’ll get some serious fragmentation and splash even at 10yrds or more. I’ve been hit numerous times on the top of the head and legs from fragmentation. It’s only because we had steel set far enough away that it didn’t break skin.
In general, we bake the warning into our stage designs and verbally warn in our walk-through but the general expectation is that you know the rules and you are responsible.
And no it is absolutely NOT the range’s responsibility NOR is it the stage designer’s responsibility to make sure you are shooting safely. It is ENTIRELY your responsibility as the one with your finger on the trigger.
If you have doubts about the safety of a stage, ask questions BEFORE anyone starts shooting the stage. Call out anything you think is a safety issue. No one should grief you for wanting to be safe