Ok those who see no problem... Let's just for the sake of argument concede that you have never had any right to privacy while crossing the border and so there is no cause for outrage here. Guy did it to himself.

How was this different from deleting the same data the day before instead of on the spot?

The argument goes that the crime is essentially knowingly depriving the police of something they want.

The problem isn't that the phone was blank, it's that it wasn't blank, and then when the authorities wanted to look at it, and you caused it to be blank to thwart them.

Ok well all of those supposed key differentiating factors also apply the day before travelling.

You knew you would be crossing a border, and knew you might be searched there, and knew you would have no right to object or resist, and so as a direct response to that knowledge, took action to deprive those authorities of something you knew they might want, by wiping your phone the day before travelling and carrying no data with you into the zone of inhumanity.

This would probably still "work" today and might have worked for him this time, but that's just luck and progression. If more people do that and the jackboots start to identify it as the source of their inconvenience, what prevents them from declaring that illegal? It's all exactly the same argument.

All it needs is to become a more common practice, and then it gets a handy name like "pre-cleansing", and then you can be charged for the crime of pre-cleansing.

Maybe we should just make it illegal to own tech that you even have the power to delete yourself in the first place. If you want to wipe your device, you can't because it's not allowed to run custom software, and even if you simply physically destroy it, they at least know it happened (and where and when) from the loss of telemetry and they have the non optional cloud storage anyway.

Then we can charge people for destroying evidence by knowingly avoiding generating it in the first place. You are guilty of the crime of attempting to evade prosecution by not commiting a crime.

That's where we are already. The current case has exactly that same absurdity.