There is no way Brad or anyone would have meant triple stop, it is impossible to sustain them all at same time. In film scores orchestrators often just write the sounding notes and the players sort it out, much easier when it is a cluster.
Some people use the word 'div' but it is always assumed that it is always div, and if you put a double stop there is a 90% chance they will divide it anyway. In my scores I never mark a two-way div. I mark a 3-way. Not because I am ever worried they will play a triple stop, but I want to give them a heads up as a 3-way needs to be worked out, where as a two-way does not.
Tim