Well.. Davo, the only thing that made me think that cutting the lead would be a bad idea is.. (maybe I am interpreting this wrong, Matt..)
The little NH next to the horn statement is read (to me) Normally High. When referincing an IC normally high is a positive voltage (ususally +5V, but could be anything, I guess). If you cut that lead, and it is EXPECTING a high when not engaged, then the cut will be considered a low.. (i.e. 0V)
wouldn't that make the horn go off continuously?)
Just raking my brain, now...
Ray