In ClearCase it's default the all checkouts are made as reserved checkouts. But if you are working in a team on a shared stream you would probably rather have the unreserved checkouts as default.
This setting can be set from the ClearCase explorer and is effective for the user on the machine, that is all checkouts on that machine. Please note that this may not be the desired option for anything but shared streams. Hmmm?
Anyway here's the easy solution: