Spotlight indexing off on USB drive insertion
I really can't remember when this behavior started since I discovered it only recently (when troubleshooting entire message search in Apple Mail).
The hard drive is a new one, the system was cloned using Carbon Copy Cloner.
Also, at some point I was trying to find a way to prevent Spotlight from indexing removable drives, but can't remember actually doing anything about it, except running Spotless for a while, but that was before Snow Leopard.
And no, there is no ".metadata neverindex" file on the HD.
What could be the reason for Spotlight indexing switching off when USB drive is inserted?
MacBook5,1, Mac OS X (10.6.4)