If I go into Spybot > Mode > Advanced Mode > Tools > IE Tweaks using a limited account, only the first of the three "Miscellaneous locks" on Spybot's IE tweaks page appears to be grayed out:
- Lock Hosts file read-only as protection against hijackers
- Lock IE start page setting against user changes (current user)
- Lock IE control panel against opening from within IE (current user)