I discovered birdtricks quite recently and I don't know if they've changed/improved their methods...? However, I have watched a lot of their free content on youtube and it has helped me with Alfie. I've never done any structured training with him before but their videos helped me learn how to start some structured training with him and honestly, it's really turned things around for me and Alfie. He went from lunging to my hands (even when I had to treat) to flying to me and accepting a treat within weeks.
I appreciate these are tips and tricks that many other trainers offer, but I've only used their free resources on youtube and that was good enough to get me going. The masterclasses and in home visitations they do have been really interesting to watch.
I don't think I've ever seen them recommending to starve your bird (but I haven't watched ALL of their videos) and a lot of the complaints I've seen seem to be quite dated and seem to involve a Chet Womach (who I think might be the brother of Dave Womach?). I've not seen any videos with him involved so I wonder if he dropped out of the birdtricks scene or hides in the background these days?
Like anything on the internet, it definitely pays to do your research and double check your sources of information. There are lots of recipes and guides available about feeding birds and similarly lots of resources for training etc. I have read lots of different books, watched loads of different videos and read lots of guides/information on the internet- I'm always learning, even after 17 years of living with Alfie.