Comment 10 for bug 746075

If it wasn't clear, the license prompt will not be shown at all if the debconf keys are set, so this indeed will allow you to pre-accept the license.

When the debconf keys are set, the package install will simply print "blah license already accepted" in the console.

I might have broken the workarounds though, since while otherwise untouched I did alter the headline of the license from "snowball click-wrap" to "ST-Ericsson Limited License Agreement" to match the name we use of it on the igloo site. But not sure how the detection works, and in any case you should be able to implement a proper way to pre-accept now.