There's some hub-bub going over at XDA about whether or not Microsoft is remotely re-locking jailbroken phones. In order to understand the process, we need to step back for a second.
ChevronWP7 worked by installing a security certificate on the phone in addition to the program--basically it's spoofing, making it look like it is a developer device by looping it back to the PC. Once they pulled the program they also pulled the certificate and people's phones were relocked again. XDA member Cendaryn managed to grab the certificate and now we can manually install it on the phone thereby re-enabling the process.
Now, a few users are receiving warnings to uninstall homebrew apps when they are run, leading some to think that Microsoft is revoking the certs from people's phones ergo re-locking them. (For the record, my Google Maps is working just fine). However, co-developer of ChevronWP7 Rafael Rivera has Tweeted that "Microsoft is NOT remotely locking your phone. Don't panic..." and that he'll clarify in a bit.
So in short, no Big Brother issues, no Microsoft bringing the hammer down stuff. Probably just a quirk of how the developer-systems checks for a valid certificate.
Update: The developers of ChevronWP7 respond here. In short, after 2 weeks the device checks in with Microsoft to see if it should be unlocked. If it is not validated, it re-locks automatically (but it can be unlocked by the same process again). Short of it is Microsoft is not targeting devices to be re-locked.
[Image credit: Windows Phone Hacker]