Subject: Re: Columbians to allow deportation flights
There may be some truth to that if the criminals are making their trek despite Colombian government sincere attempts at intervention. In that case Trumps accusation would be better expressed as "Columbia is failing to take effective measures to interdict Colombian criminals attempting to leave Colombia for the USA."

Even if Columbia isn't taking any measures to prevent people from leaving the country, they're still not "exporting" anyone. Most countries don't impose any restrictions on people leaving the country (other than security states like North Korea). Here in the U.S., a citizen faces no restrictions at all if they want to leave the country - they're free to go anywhere that they can get into. It's not Columbia's job to prevent people from leaving.