Have you ever carried a can of petrol in the boot of your car? In the summer I regularly carry 3x20L gerry cans to my boat, and even with the Mrs driving I haven't blown up yet....
I'm sure your plastic cans will withstand more than enough G force to allow the flight to be made in complete safety, even if not legal...I should imagine the wings would fall off before the can ruptures.
CU
EA