It's understandable that people would get upset so quickly over the situation given how it could potentially have a terrible outcome. If you are doing multiple sets at weight that pushes your limits you need to ask for help from others or find a smith machine with a safety on it so that you do not harm yourself. Using the pins is a clever idea but eventually you may get to the point where a pin won't be able to hold half the bar safely. I think that it is better to break the habit than let it get that far.
If you are trying to gain strength you may have to lower the weight and raise the reps or sets that you are doing for a while until you begin to understand your own limits. The most important thing about body building or lifting weights is knowing your own limits so that you do not harm yourself. It took, and still takes me on occasion, a long time because I can easily become over stimulated at the gym and lose sight of what I am doing. You must focus and take note of what you are feeling. I do understand that muscles can give out at times too so you need to take that into account as well.
The embarrassment of having the weight lifted off of you is fleeting, the pain of having weight drop on you lasts much longer.
Be safe in your endeavors!
That said you may want to look into other strength training exercises and methods such as dumbbells, cables and standard sets of 5x5.
Keep at it, don't get deterred!
_________________
"Power is the reason that we all are fighting for, control your body, your soul and heart. Yes- some of us who surrender are like lambs to the slaughter; get the power & try harder to reach the next stage."
-SMT III