Sorry, should have specified it was going INTO the US.
Was on Spring Break down at Padre back in '95 or '96, Matamoros is nearby. Apparently you can just mosey into a "doctor" office and they will write you a "prescription" for just about anything as long as you give them a nominal prescription writing fee. So me and my buddy obtained a couple of prescriptos for some crazy stuff like Decadurabolin and some other kind of 'roid that I couldn't even pronounce. Then you can take the prescription into the Mexican version of Walgreens and they're stocked with the stuff.
We took the doses out of the boxes and put them in little zip loc type baggies, then hid the baggies in out pants. It was pretty nerve-wracking walking thru the little customs room they have on the border but we knew they rarely even pat people down. Kept thinking about that movie Midnight Express. Interesting thing is the roids wound up getting sent to his cousin who was going to school at....North Texas!!
Allegedly, of course.
i was with a guy in that same time frame that snuck about a dime or so back over the boarder. the guard guy has to look at your drivers license and ask if you are taking anything back. as long as you just say no, you get to keep walking. my intoxicated friend says "yeah, i've got some wheat". the guards goes "weed, you've got weed?". my friend is "no wheat. we're from kansas. wheat. i was trying to make a joke." quite possibly the dumbest thing that i've ever seen anyone do. the guard hassles him for fifteen seconds while the whole time we just keep walking.
We drove into Matamoras (WTF were we thinking??) and when we were driving back over they asked if we had anything and we said no all nervous and they completely tossed the car even having a guy there to take off door panels and stuff. Never frisked us or brought in a dog or even made us empty our pockets. Completely set us aside and shot the cac with us while they tossed the entire car for about 30 minutes. I don't know if it was a pain in the ass to get authority to check our pockets/pants/underwear/etc. or what and I wasn't sticking around to ask.
you guys drove into matamoros 
Yeah, W...T...F right!?
i just can't even imagine. i mean, wow. pretty incredible really. maybe the craziest thing that i've ever heard of though too.
One of us (not me) spoke Spanish and kinda knew what was up and we found some old guy standing on the street where we parked and he talked to him a bit. My re-inaction of the converstation:
guy I was with: duche shat as gisda tia;;g sahsia;t asdgio a aeih g ;as g ire
this guy: sadf o ;f as ;aeae sdfh sdfhasu ausduubv xx ziduf
guy I was with: (hands him a 20) asd i bzzxzbv ziv wiuerhwbB WEIUOID VOIADVBAW WUEBR
this guy: (shaking his head and pointing around and then pointing at the ground) sld bd fuil ois dosif bbqliu ubsdliue uawbia vbuasldiu;g
And, in summary, the guy on the street sat by our car and smoked cigarettes and it was there when we got back and he was still standing there smoking cigarettes when we got back and we drove back across

Guy I was with was all, "Yeah, told him I'd pay him to watch the car and the guy was all "Yeah, you're lucky you did" ".