I don't think anyone here can comment on any specific recruiting requirements that you may or may not have seen. If you do see a job ad popping up saying something like that, by all means contact their HR and ask. I've never seen any airline being that specific, I certainly don't think it's a norm.
I would assume most modular guys have seen at least 2 or 3 training providers during their training, some many more, so I wouldn't worry about it