Even if you drop the word practice and change it to internal policy, that does not negate the risk of them suddenly enforcing the publically published policy (say that five times fast!
) I mean, someone wrote that external policy for a reason. I don't think they wrote it not to use it.
Personally, I would not spend a bunch of money relying on getting 100% back. I would spend it expecting to only get 90% back if I had to cancel and if I get it all, that is bonus.
Again, maybe the risk is small, but I do not think you can deny that it is still a risk if you buy a ticket with that policy published on the website.