There has been at least once incident involving damage to remote geostationary satellites by a misfiring silane rocket motor (need cite) 
.

The risk of deliberate such damage, particularly with respect to m288 [[http://books.google.com/books?id=FoSOD7fRdjAC|orbital debris doubling time]], needs quantification for rational comparison to the military vulnerability of alternatives.

Silane has an Isp of 340s yielding an exhaust velocity of:

[[http://www.calchemy.com/uclive.htm|340s;grav ? m/s]]
= 3334.26 m/s

Silane would have higher exhaust velocity but for the early condensation of quartz crystals resulting in lower expansion-bell time.