I'm not sure and am no expert on the subject so take my comments accordingly.
Your question is an interesting one. I definitely wouldn't cut the truss plates without getting an authoritative answer first. On the other hand, the purpose of a truss plate in my understanding is to hold the wood together and I can't see where the portion not attached to the wood is doing this, but it could be providing some additional resistance to shear forces. As I said, I'm no expert.
There are a few places you could go to get a good answer:
The first would be the manufacturer of the trusses if you can find out who that was or can find any indication of that on the trusses themselves. Trusses are usually manufactured fairly close to the job site so the manufacturer shouldn't be too far away providing they are still in business. If you know the builder of the home they may know who made the trusses.
The second would be the Truss Plate Institute, here is a link to their website...
http://www.tpinst.org/
The third would be the truss plate manufacturer. There is probably a marking on the plate indicating who that was. There are only a few major truss plate manufacturers in the U.S. The list of those belonging to the TPI are listed here...
http://www.tpinst.org/platemembers.html