The main issue is the safety of the food in canning.
The second issue is when sent to an APO / FPO box for an AE delivery, if any liquid or glas is detected in screening the package is pulled and discarded.
If it clears US customs it then has to clear Foreign Custom inspections.
My legion Post ships about 25 packages a week and have had to deal with many issues of loss from simple issues like shampoo and liquid soap.
Can't imagine a glass container filled with meat and juices getting through...
Humphrey's DownEast Beast W/BBQ Guru