That is a crime under the CFAA in the USA. Not sure what it is in Germany/EU.
The prosecuting attorney is going to tell a jury of twelve of your non-technical "peers" that it is hacking.
Your client can either go to trial for seventeen thousand two hundred and eighty nine counts of felony hacking, and risk half a million years in prison, or they can plea bargain to 5 years in prison and a felony on his record.
Or your client can hang himself, but I'm pretty sure a federal prosecutor counts that as a win too.