Ready books by Bhai Randhir Singh ji and then come to the conclusion by yourself. You will not be able to get an instant gratification answer here. Google age instant answers are always wrong and one cannot know the others by reading few opinions here or there. Self research if serious to learn. Read his books, put quotes of him for further discussion here otherwise you won't learn anything. 

How would we account for this next time? Can this be mitigated at all? 

Yh, a lot of the corrupt policemen were from Sikh backgrounds. Have you heard about ghotna? His sister lives on the road next to ours. She came to the UK back when they used to come in those ships. He was from the Jalandhar area. He got the name ghotna because of the torture tools he used, one of them being a huge wooden roller, ghotna. He used that to crush the knees of the Singhs. He used to come to the UK when he retired, to visit his sister. He used to wear hats, black shades, scarves etc try to disguise himself, so no one recognised him. When he died the hazoori raagis refused to attend his funeral.  I never saw him because I was a kid back then but my dad and others talk about him coming to the UK.

looks like escrima philipino knife art which I mentioned before apparentely he has filmed tutorial style  available here: https://www.aperture.university/store/FyXFXwWP

What hurts more is that most of the time it was our own. Everyone was trying to get their sons to go abroad and leave Punjab because of that.