The incident:
I was preparing to board a flight from DFW to China for a 2 week vacation. I scanned my boarding pass and began walking towards the skybridge to board the plane and a customs agent stepped in front of me and asked if I was carrying more than $5,000 in cash on me, to which I responded "no". He then said "okay, we are doing a test today, you get to help us out with this test and can tell your friends about it won't that be cool?" and had me put on a jacket which looked roughly similar to the one I had on. I thought "okay, this is kinda weird but whatever I'll help you guys out".
I should mention this guy had a thick Russian accent/imperfect English, but his uniform looked legit. At no point did he mention participation was optional. He held onto my passport while I put on the jacket (over the jacket I was already wearing) and I proceeded to walk down the skybridge towards the plane, but he almost immediately stopped me and said "walk slowly". At the other end of the skybridge there were about 4 - 8 TSA agents and a sniffer dog. At this point I got skeptical of the situation and started feeling around the jacket expecting to find some sort of contraband, and ended up finding a brick-shaped lump of what I am guessing was either drugs, fake drugs or cash either in the jacket pocket or sewn into the jacket itself. I held up the lump inside the jacket and looked toward the agent with a 'wtf?' look on my face, to which he responded "it is currency".
At this point I became even more skeptical, took off the jacket and returned it to the agent and asked for my passport back. I then proceeded to board the plane without the jacket and the TSA agents reacted with a big "aaaahh man!" as if they really wanted me to board the plane with that jacket on.
This was my first time flying overseas, but I'm guessing this isn't standard procedure.
Has anyone experienced something similar to this? Did these guys attempt to plant drugs on me? What's going on here?