Is there any way for a trip to Buenos Aires flying to Montevideo to save money could backfire?

Posted by joshua0005@reddit | Shoestring | View on Reddit | 16 comments

My plan is to go to Buenos Aires and then to go Peru to see Lima and Machu Picchu. One-way flights from my city to Buenos Aires are about $190 more expensive than one-way flights to Montevideo.

I would then spend a couple nights in Montevideo and then take a ferry to Buenos Aires. Now I know this will make it end up costing about the same as just flying to Buenos Aires, but if it's roughly the same cost I might as well add Uruguay to the list of countries I've visited even though it won't be a very long visit it still counts.

This is a bit hacky though so I'm wondering if there's any way this could backfire on me that I'm not thinking of.