Same, I have never found my nicklists to be unresizable because of locking the bars, and have always assumed that option was only intended to affect MDI window components (as opposed to MDI window windows).
You could try setting "Border size: 1" under ALT-O > Display > Options > [Styles]. That reduces the size of the nicklist's "dragbar" to one horizontal pixel, which greatly minimizes the chances of accidental "catches" when mousing for the scrollbar.
