How many times!! Advice please...

My neighbors have puppies, they moved in at the end of May and a week later
brought home two tiny pups that live outside except at night (if the ppl are
home) we get the usual barking etc. that is not a problem as most ppl here
leave their dogs outside 24/7 so we are used to it here is the problem---
My SO and I came back from vacation early and on 7-15 heard awful noises
that we couldn't identify, my two dogs start whining and running to the
fence then in the house so I went to check it out and the puppies were at
the fence line and one of them was barking and digging and the other one was
making this horrid noise. I couldn't really see what was wrong but it
looked like it had a branch through it's neck... so I jumped the two fences
to get over there and it's collar was wrapped around a branch, luckily I was
able to get it because it was a clip collar..
So I took both dogs collars off cut the branches and left them a note to
call me and when they did I told them about breakaway collars and how
dangerous collars can be especially with two rambunctious little ones and
they started taking the collars off the pups during the day until two days
ago and this time the pup that almost died last time had it's jaw caught
under the other pups collar and my neighbor jumped the fence and got them
separated... Both incidents have happened at times when the owners will not
be home for hrs..

I have explained the risks to them and really worry about the day coming
when no one is here to save them. Is there something I am missing or
something else I should try???

Thanks,
Michelle