The compliance with this law is anecdotally very poor. Swiss Airlines owes me thousands of Euros for missed connections but they contend that the situations were outside their control (some mechanical issue) and thus they refuse to compensate. I have a 200 long thread email chain spanning years with no progress. You can use services like Airhelp to get a refund but they take a huge commission and I am too stubborn to give in that way. Luckily the statute of limitations on these claims is 6 years so I have enough time to figure out how to make a complaint to the Swiss aviation authority.
Scanning a forum like flyertalk shows that most airlines basically refuse to voluntarily honor this law without being forced to in court (not even the threat of a lawsuit will get them to pay, you actually have to file it).
Scanning a forum like flyertalk shows that most airlines basically refuse to voluntarily honor this law without being forced to in court (not even the threat of a lawsuit will get them to pay, you actually have to file it).