It can certainly be done. You can always do a "pacman -Su" later, if you want.
The problem is that I want to check for updates in a script. 'pacman -Sy' without upgrade can cause problems.
In your use case, you can probably specify an alternative db path using the --dbpath switch in pacman.
That's what I wanted to do, but dbpath countains the local and upstream databases, so I thought it might cause problems.
