Oh I don't feel sorry for the guy at all. He is scum and will be locked away, as should be.
I just fear empowering the cops to use the tactics that they use in cases like this, because I know A LOT of people who think it's OK for them to go poking around in citizens' banking records or even into homes based on "anonymous" information, using the same "if you are not doing anything wrong" line of reasoning.
If at any point he had just stopped communicating, or if he had not travelled 1200 miles to make the meet, or if he had not followed the officer into the restaurant, he could have walked away. The police did not act in this case until the moment when a child would have been endangered, had it been a real seduction. That strikes me as being about the right balance.