You will find this quite common now with the Sifus in HK and China too, as the MMA world has had this effect on the more Traditional 'One Sifu for life' teachers like my own. Chinese MMA has been going on for quite a while now too, say more than 400 years
LAY is also a Sifu of Hung Gar isn't he? And Taichi? Being a practitioner of other Southern Arts too, he will always be open like that which is a great way to appeal to the MMA types.
When you are restricted by your Sifu from 'touching hands' with other lineages it is sometimes because of their own insecurities, knowing that the 'roll' will be different and sooner or later end up in a fight/spar of sorts anyway. I also find it's because they are hidng something too, like a lack of true understanding, and the only way to 'exchange' is to have patience and share eachothers methods over time. This way both parties will feel eachothers way and benefit accordingly.
I would hazard a guess here that even within ones own lineage there will be differences in rotations and chisau practises. I know this is true from my own experience meeting and exchanging with my own family members, and each way has its strengths and weaknesses.
But if we are to talk about weaponry, and how to promote the knives especially in a stylized cinematic way, I have yet to see anything as appealing as the work Sifu Leo is doing. His experience working in the HK movie industry has obviously had a good influence on his artistry... but I understand that isn't everyones cuppa tea!!