The problem is that the definition for hacking is overly broad.
It is clearly advised by the published guidelines that an organisation should define for themselves what they consider acceptable and what's not acceptable. An organisation might, for example, rule out social engineering attacks or DDoS.
IT journalist Brenno de Winter calls the guidance useless. "If hackers first have to report the vulnerability, they lose their anonymity without having a guarantee that they will not be prosecuted. And even if a company promises that it will not press charges, the Public Prosecutions Department can start a case."
A published responsible disclosure policy is a legaly binding document. If a organisation states that it find's certain behavior acceptable and even clearly states that it won't take legal action against people holding themselves to that document they have to follow that promise. As for the public prosecutor there are two parts that will protect responsible hackers. The first is the fact that the crime of hacking (computervredebreuk in Dutch law) requires the access gained by the hacker to be unlawful (wederrechtelijk). When a company states that certain behavior is acceptable, the legal test for wederrechtelijkheid will fail and the public prosecutor will have no case for the crime of computervredebreuk. Further more, the Dutch minister Opstelten has promised to talk to the public prosecutor about how they will handle responsible disclosure cases. Given the well thought-out contents of the released documents and the clear intentions of the gouvernment I have no reason to doubt the results of these talks.