One way ticket Panama Colombia

Hi,
Just thought Id share my experience as this has been previously discussed here. We bought a one way ticke with Aires from panama to Barranquilla. I was a bit concerned about not being allowed to board because of the onward ticket rule. We first went to Avianca to check if they had refundable tickets. They said we didnt need an onward ticket and Avianca would always allow you to board. She said something like "you are English, you have credit cards, why not?" She told us to go to Aires. I didnt think they had offices, but it was nearby. There they said no problem, again mentioning credit cards. The young guy who told us this was at the check in the following day and sure enough, no problem. So, it seems you can board with a one way ticket. We are white and middle aged and indeed do have credit cards, so I cant predict how travellers of a different appearence would be treated. Hope this is useful