How sad.
I also knew a waiter years ago who saw the same in his upscale restaurant. He started collecting food from his own and other restaurants and from the supermarket delis in the neighborhood. After he got the routine perfected, doing it all on his won time and even doing a mini meals on wheels program, he had to shut it down.
The health implications are obvious so maybe nothing can be done but it is a shame.
There's one restaurant near me that pours bleach into the dumpsters to keep anyone from eating the food thrown out. I'm quite certain they aren't doing it out of worry about lawsuits. They just don't want bums hanging out back of their restaurant, I guess.
What I'd like to do, but can't afford, is to reserve a table for 12 or something like that, then go round up 12 homeless guys, take them INSIDE that restaurant and buy them all a meal.