Because it may not survive the reboot.
Especially if it's a power issue.
On the other hand, if they can get telemetry first before rebooting (which they can always do as a last resort), they can do some actual debugging instead of acting like NT admins.
Now that Spirit has responded with 20 minutes of data, I'd say that the NASA guys are right on with what they're trying to do. Your solution is a last resort only.
Regards,
-scott anderson
"Welcome to Rivendell, Mr. Anderson..."