More longer friend see that sky?

Trying to capture travelers from the future is an inherently disadvantageous situation. Being from the future, your prospective captives already know the lay of the land and the overall historical forces at work at the present moment; the great uncertainty of what is to come has become the epitome of certainty. While the particulars might elude their grasp, the general overall picture will serve them well enough for the purposes of escaping

However. This foreknowledge can be used against them, especially in cases when they try to blend in. Knowing the future means knowing things that are unthought of and possibly even unthinkable in the present, often to such a degree that the unthinkability has faded into the mists of time. Thus, the way to trap them is to make impossible statements invoking every flight of fancy imaginable, and see how ruffled they become. Those unaccustomed to telecommunication, for instance, will balk at the merest suggestion of it, while those whose lives are permeated by it at every turn will barely blink at the notion

And that is their undoing. That is how we shall get the bastards