Comment 2 for bug 151300

Safe graphics is more about loading a driver which is likely to work (and not crash your machine), rather than about mode detection for your monitor.

Yes, some bugs can cause damage to an LCD, but those are more specifically related to mode-setting bugs with internal laptop LCDs. Even then, in most cases they are protected by hardware lockouts. An external monitor should auto-protect if its refresh range is not what it can cope with. (Older CRTs might fail to sync).
Did you observe any adverse symptoms on your monitor?

Monitor detection and mode-setting is something which has been improving a lot recently. Does the issue still persist in Gutsy?
If so, please attach an Xorg.0.log from the server when it detects the mode with high refresh rate.