Not really scam but the thing that get on my nerves into walking inton the usa otay border..on the Mexican side. When the line is like 45 min to hour long which is not that long compared to San ysidro line.. what people will do is stand in line and once they get in front of the line the will stand by the walk and ask for 10 to 20 dollars usually 20 dollars to trade places with you and once they trade places with you and see you go thru they themself will cut in line and stand near the walk and trade places with someone else and reoeat.. and they sometimes act like it's an official thing that there allowed to do which it is not..
The usa border patrol does not care cause it's not on their side or it's like a neutral side. I only seen the Mexican police kinda of stop it but they don't have time to deal with petty stuff like that unless the crooked cops are getting a cut from it .
What this does is slow down the line even more..when they had more agents in USA line went super fast ..
But thing I do like about otay mesa lines walking across you have more performers then street beggers so at least in entertain waiting thru lines and the street vendors