Packed it myself but....
I have just returned from Guatemala. I was not asked if I had packed the bag myself or had left it unattended. Went through security and my carry on was pulled. The lady went through it and gave it back.
At the departure gate it was checked again, no problem. While on the plane I opened my bag to get out my headphones. Horror... I had been given, two weeks before, a freezer bag and inside were two large gel packs, maybe half a kilo each. What do you do? Report it to the cc and risk being escorted into Miami with a fighter aircraft on each wing tip or ignore the fact and hope it will be ok? Decided on the latter, got to Miami, went through immigration and dumped them in a trash bin outside the airport.