I don't know that I agree with your analysis of the solution in Eleventh Hour... the whole "send out a virus and then have them track it back to the phone" is very standard "________ doesn't work that way", which to me is an integral part of the show (see also: SONIC screwdriver). The ultimate solution did flow from what they'd established about the thing and its shapeshifting. It was a little hurried, but it was hardly a matter of "Of course! I just remembered that all transdimensional multiforms are vulnerable to citrus fruits."