I fear you maybe right. I might point out a few things though.

1. I would hope that an immigration officer would not discharge his gun in a crowded airport even if he was hunting a drug mule or a wayward papaya.

2. Since when is it the job of outbound security at any airport to screen for drugs, they seem to have a hard enough time checking that our water isn't explosive to we really need to give them something else to make sure we are not carrying?

3. As for jerry_pharm's example of Nicaragua, wouldn't it be more likely that it would come across the pourous land border between US and Mexico?