Another good reason to lock your wi-fi because bad guys love to find unsecured wi-fi to surf CP or whatever criminal acts they're engaged in.
I've brought up the "steal an IP" scenario, before, here. All they have to do is get on a public WiFi, grab the IP address, and use it with a proxy/VPN/whatever, and be able to browse/surf the interwebz anonymously. Easy to do, get on a public WiFi and merely look at the address on a smart/iPhone or similar device, at the library, a restaurant, etc.
I've been waiting since the hunt for the killer began for people to start bringing this up. Remember what one of the LE guys the first week of the investigation, something to the effect of keep an eye on your kids' online activity. That has stuck with me.
MOO/possible scenario, perp is at the killing spot or thereabouts for a period of time, watching the bridge. He knows local kids have the day off from school. Perp has recon'd the area in the past, maybe even fished there, etc. Using a non-traceable Android TracFone (available at WalMart, Amazon, etc,), is able to surveil SM or at the very least websites devoted to the Monon High Bridge for people 'checking in', or who are 'there' or who are taking pics for SnapChat and whatnot. Maybe Libby checked in, or at the very least was tracked via the SnapChat shot she took of Abby. Who knows?
Perp waits, watches the bridge, maybe even has a set of binoculars. Waits until the girls are a fair enough distance across it. Starts walking towards the NW end of the bridge, along the creek.
Girls see him on the opposite creek edge. Perp gets on the bridge. Girls get nervous, Libby starts recording when BG gets over half way across the bridge. The rest is history.
I can't stress enough that there might be an online connection with this case. People have inadvertently posted things online and become victims of crimes in the past, even been murdered. This blows a huge hole in the whole "he's a drifter" theory.
JMO