Normally events seem to have decent drop rates of the items required for them, but this week it seems like keys are being dropped substantially less often than they normally do, and there are quite a few people upset about it.

I've gone through 340 stamina today and have received 2 keys, with more than a few of the people in my group reporting similar situations (290 stamina for 3 keys, 380 stamina for 3 keys, and 160 stamina for 1 key). It seems like this is just dangling a carrot in front of F2P players that a lot of days they can never reach without using stamina potions. I thought the entire point of offering events like this, with chances to obtain free keys, was to allow players to get some rewards without having to spend money.

So more of a question than anything, but is there some kind of fixed drop rate for these, where you receive one at least every X amount of stamina used? If so, what is that drop rate?