Do you guys advise people who're using improper form when training? And how do you react when people ignore your advice?

I was at the gym today when two guys came in and started dicking around with the gym equipment.

One of them was benching some pretty heavy weights and his friend was spotting, and all of a sudden the guy couldn't push up the bar.
What did he do? He just let go of the bar thinking his spotter could save him, but his friend couldn't lift it up so I went over to help. He didn't even secure the weights and they naturally slid off the bar and fell to the floor. I told him that he was benching too heavy and he should secure the weights; he just waved his hand dismissively and grunted.

Later, the spotter guy was doing some cable lat pulldowns, but he was using his waist to help pull the weights down, and kept leaning back and bouncing up. Yet again, I said to him that he was using improper form, and he said "yeah I know, i'm doing heavy weights".
As far as I know, doing heavy weights doesn't exactly excuse you from using proper form does it?

I then said that it wasn't the way to train, but he just ignored my advice and continued doing it. Suffice to say, I simply ignored them for the rest of the time I was there.

But I can't help thinking if I should have made more effort to explain and convince them to use proper form. And yet another part of my mind urges me to simply ignore all those guys who're ego-tripping on lifting weights using bad form, and let them learn about serious injury the hard way.

I admit i'm still considered a beginner, and my physique isn't exactly eye-popping yet, but does that mean I am not qualified to give advice about form?

Lol, PSP gym workout.