Julian Cope presents Head Heritage

"It is true that many of the more sensational stories of German “outrages” perpetrated in Belgium during the course of the invasion and ensuing occupation are very hard to believe, much less corroborate. German soldiers eating Belgian babies; German soldiers hanging Belgian nuns between church bells and ringing them to death; German soldiers crucifying dozens of farmers by the roadside; and so on — these are stories that are familiar to us through the fact of them having now become standard examples of why “propaganda” is not to be trusted."

http://ww1centenary.oucs.ox.ac.uk/memoryofwar/the-rape-of-belgium-revisited/

As there's no corroboration with any of the more sensational propaganda stories I'd tend to be wary of what Rubinstein suggests. If he was there then he'd be in an ideal position to fuel the anti-German fervour and the need to go to war. Backtracking on that later (in his bio) could have lead to a number of very costly lawsuits.