[yourenotsmart]

No one builds a RFID system because one guy really needed water that one time, can we at least be serious here?

No one is discussing some hypothetical situation where someone knocks on your home, either.

We're talking about a problem that's systematic, at volume, and persistent over time, and therefore qualitative change for McDonald's and the environment they offer to customers.

McDonald's wanted to offer finite refills to paying customers. Their current system had a loophole with unintended consequences, so they closed that loophole.

If you want to help homeless people I guess go work at McDonald's and give homeless people water when they ask, and everything will be perfect. But let's see if your ideals stay intact after 10 cups of water. 100 cups of water. 1000 cups of water. A million cups of water.

It's very easy to say "oh I gave water to a dude once". I also gave water to a dude once, doesn't matter for McDonald's and people habitually coming back to leech a resource they provide that's not intended to be free in the first place.