Haha, only someone in the management position would fail to see how making something like that mandatory for everyone would ruin the fun of it. xD

You see, we who started it and were the most active in 'providing' were doing it out of pure joy of it, we weren't at all concerned about keeping the tab of who ate how much vs how much they contributed. It was only the Team Leader who thought it was not FAIR!

The difference between voluntary and mandatory is the difference between -
"Oh, it's Friday, I feel like surprising my team mates on a whim with something fun, let me go and grab something from store. ^^ "

and

"Oh, f**k, I forgot it was my turn to do the Snack Duty this Friday, I have to quickly run to the store or the whole team will be angry with ME, specifically. douh"

And that is for those of us, who originally WANTED to do this. Imagine the ones who had little to no interest in the whole thing in the first place, I'd imagine it would go something like - "F**k, again this f*****g bull****t!"

I'm sure some would even question the legality of mandating spending one's own money on the team like that, since it wasn't from the team budget but out of individual pockets.

One thing that's important to remember - you cannot mandate FUN. That's just not how it works and always backfires sooner or later.