[zorrophreak]

As far as I know, an IP address will only give an approximation of geolocation

Correct.

And It's that of the ISP, not on a personal level.

Sometimes the geolocation will even show a different city/state. Main reason I don't find this story plausible. Unless the abductors work at an ISP.

Again, seeing that it just redirects to your usual scam ads for free giveaways, I am almost certain that the stories are just a scare tactic because so many naive teenagers are receiving these messages.