Here we see how the open borders work. A terrorist can go from germany to italy with no trouble. Fantastic. Good to hear that the police got him.
Yes, let's screw up the lives of everyone living in Europe by reintroducing border controls and introducing mandatory visa checks of every passenger in every train because there is a terror attack sometimes.
You can go full state of emergency and even deploy the army everywhere, control everything and make the lifes of everyone unpleasant (not to mention the paranoia and discomfort it causes among the general population) like in France. Didn't prevent the attack in Niece. There is no way to stop every single lone wolf attack no matter how much you try. All it takes is one radical with a handgun (or heck, a baseball bat) or a car and you'll have at least several dead people.
And we don't even know how many potential terrorists DO get caught by investigations and surveillance before something happens ... there is a reason why this is the worst terror attack we had in Germany in ten years.
Of course you can crackdown massively and limit civil liberties like so many in this thread suggest. That only aids the terrorists in achieving what they want, curtailing our way of life,
everyone getting affected by security measures resulting in distrust, fear etc. etc. France has been in a state of emergency for how many months now and has to deal with resurgent right wing nationalists and racist intolerance towards and attacks against the muslim minority which only escalates the situation more and more. That deals far more damage than the terrorist attacks themselves.
Of course you shouldn't stick your head in the sand, but full on paranoia, police and surveillance state is not the way to go either. That the suspect did get caught shows that the net of police control is really tight, in fact I can't remember one suspect of any of the notable terror attacks in Europe since and including the Paris attacks (and even Charlie Hebdo) actually escaping, those not dying during their respective attacks all ended up getting caught in street controls or their hideouts were found and raided by the police within a month or two. They all end up getting caught after crossing European borders one or two times at worst.
The fact that he left his documentation in the truck seems to have sparked some conspiracy theories, yeah
People still don't know this is a proven ISIS tactic especially if it serves to "show" that the terrorists arrived as refugees (even if they could get into Europe far easier, but making the population suspicious and paranoid of refugees is what ISIS wants, increases tensions and gives them more potential recruits and good propaganda material)? They already did that during the Paris attacks over a year ago.