Anyway I saw a video about it and witnessed how the participants are lacking a simple skill of folding and fitting the A4 paper into the envelope well, this is not good (for our image). There should have been some instructions given to the participants on how to do it (professionally). It is also a public stunt. I saw the video and remembered on how my elder brother rebuffed me as an student once. I simply took my paper back then and folded it into 4 equal size shaped fold and put it into the envelop, which of course didn't fit in.
I saw someone doing the same thing I did back then on the following video and said let me share on how to do it simple. It is simple but may have repercussions.
Here is a simple instruction on how to do it right, here it is with a windowed envelope but can also be equally used for a one without a window one, I do all the time the same as it here.