IMO it won't make a fucking difference. Coaches and students will find ways to beat the testing just like in every other sport that is tested. Bribes/masking/sample switching - everything you can think of. After all, it IS the highschool players that move onto college football and if your not a teen juicer your not going to be able to compete against the ones who are.
Football is out of control in the US IMO. It is like the national religion of the states for christsakes. Not the kid's fault though, its the fans'. Just like the fans transitioned bodybuilding from the physique era to the mass-monster era, fans and spectators are putting the stress on these kids. Face it - you want your team to win at ANY cost right? You also pay to see fierce bone-crushing and aggressive competition. Nobody wants to watch a "gentlemen's" game of football, hockey, rugby, <insert favorite contact sport here>. People want to see ruthless competition
Look at it this way - what does the average fan of bodybuilding want from their Mr.Olympia? The largest, leanest and most vascular alpha male specimen in the world right? You think natty competitors stand a chance at taking the Olympia? Hell, when was the last time we had a Mr.Olympia below 250? If people wanted to see anything less than muscle freaks on the covers of MD and Flex, they would buy Men's Fitness instead. There's the pressure right there on the judges whose asses are wtfpwned by the IFBB which is in turn a slave of those that endorse the events. And who is pumping money into everything at the root of it all? The Fans.
Sorry, went off on a rant there. /rant off.