What probably would have happened if the police were involved? This device would have been sealed in an evidence vault while the police investigate, and hardly anybody would ever know about it, whether these particular criminals were found or not.
Instead, it's on the front page of Hacker News, and a LOT more people are aware of how sophisticated skimmers have become, and will be a lot more careful to check for skimmers on ATMs, and probably start warning family members and friends. IMO, this had a much more positive impact overall than anything the police would have done. But perhaps my opinion of police does not apply to Austrian police...
While waiting for the police there's nothing wrong with making a video. Taking it home to inspect it? That's something else entirely.
In terms of this as valuable education, lets put our critical thinking hats on. Did this ultimately make the world safer and help real people? Likely very little because most people have zero liability for credit-card fraud and if we think through this a bit more maybe it makes the world more dangerous.
What happens when someone who watched this video decides to do the same when they find a skimmer in Mexico, but someone from the local crime syndicate that placed it there see's them remove it, then follows them until they have a chance to take it back with force? Now someone gets hurt.
In all cases, immediately call the police.
EDIT: and if you don't trust the police, leave it, walk away, and anon call it in or call the bank.
I would agree it is completely stupid to remove and walk off with an ATM skimmer in a foreign country, all before calling the cops. There are so many ways that could end badly. There's nothing informative or educational that couldn't be shown by pictures or videos at the ATM and calling cops right away (the poster is now claiming he did call cops when he was able to get to a phone; this is still not impressive).
However, this is an ATM skimmer + PIN cam. Not credit card fraud. Debit and ATM cards have much less protection. Consumers have 0 liability for CC fraud; when but your card is skimmed and PIN is stolen your checking account can get emptied, and you potentially have the burden of proving that it wasn't you using your card in a card-present, PIN transaction.
a) not report a crime & b) take evidence from the scene of the crime
because the police likely don't care, are incompetent, and have no resources?