This is really something that I think that you can give some thought to. I'm not singling out unions here. I speak from our experience in dealing with all kinds of large organizations where they are dealing with competing resource interests. Training tends to be something that many don't like to spend money on, so when they do training, if there is a booklet people can read or an online module that they can quickly flip through, that's an attractive training method. What we know from our experience is that it often can be completely ineffective, depending upon the product.
So often, we have the opportunity to go into organizations that we're privileged to work with and to have really meaningful and deep conversations with employees about what this behaviour actually is, to answer their questions, and to have case studies where we can challenge them to deal with the situation and talk to their co-workers and figure it out. We can see how effective training can be.
The other thing I'll add is that we're not naive enough to think that even the best training is going to make all workplace problems go away, but the beauty of training is that it teaches people how to deal with issues when they come up in a live way so that they really know how to address them.