In my experience, enforcement of rules on Aerolineas is very (very) variable. If you are able to charm your way through check-in and smile a lot, chances are when you board the aircraft you will not be hassled.... of course, this depends on how full the flight is, your luck of the day and who is at the gate.... its a coin toss of sorts. Not sure this post adds any real value to answer your question, just take it as another data point (with a pinch of salt).

Have a great trip !!