I just installed Lookout on my DX and PC. Everything seemed OK. I ran a virus scan - no problems, then did a Find my Phone from the PC with GPS enabled. It ran fine, showed the location properly, and sent me an email, but then the screen went dark, and the DX wouldn't respond to my attempts to revive it via the power button for several minutes.
I was going into a mild state of panic, ready to pop the battery, when it suddenly rebooted itself, and came up normally. That gave me quite a scare, and I've never had the DX behave that way for me before. Needless to say, I'm a bit uncomfortable with Lookout right now. Beyond that, I wonder about the wisdom of sending an email which will be received by the phone, which would tip off a thief that it was being monitored. If I decide not to just remove Lookup, I need to investigate if I can substitute another trusted email address that the DX wouldn't receive.
Finally, there doesn't seem to be any provision for turning on GPS remotely. I know that if the DX is running through Wi-Fi, it will give off a location that is about 75 miles away from here, which would make that data worse than useless.