I don't thenk there were many... Around 300 total, at the very best. Most are getting stolen in 3 seconds after spawning by campers/macro users, besides, i go look for them quite rare, since thre are none, or 1-3, usually, anyway, and most of those keep saying "i was too late, someone have already opened that, key won't be used" when i try to open them, no matter i'm trying to keep my Friend list clear of campers/macro's and people who have people that i clearly know are doing that shit on their friend lists, and no inactives for "more than 1 day".
About my boxes opened by others - i can't really tell - they were many, but very few glod and not much silver - most people are just hunting for pinks and skip gold/silver. I guess i had around half-page to one page of my golden boxes open and a couple of pages of silvers. for the keys i got - i think it was around 10-20 golden total and about 15-20 silver per day or so... And i never got more than 50 Trophies from those. Mostly just 10.