Carriers release them, then Android hackers crack them open — as we see today with the HTC Wildfire. Paul O'Brien (a name we all should know by now) once again circumvents the protection schemes carriers and manufacturers put in place and has rooted the HTC Wildfire. The method (see source link) doesn't look very difficult, providing your Wildfire has a bootloader version of 0.80 or lower, and a ROM version of 1.14.xxx.x or below. You can check this by booting your phone while the back key is held — the 'HBOOT -' line needs to be 0.80 or lower.
We're all happy to see Android gurus rooting even the less popular devices, but it raises the question — should handset makers and cellular carriers really spend the time and money to put these restrictions and roadblocks in place? So far, it isn't working too well and the model that Google used with the Nexus One (making the phone easily unlocked, but then branded as such permanently) seems to have worked well for both sides. Maybe the money could be instead spent on tools to find those who abuse or otherwise cause a ruckus on the network vs. the losing war against opening the software on the new devices. Guess that's why I'm not in charge of anything :p