After /u/IanIronwood wrote his [FR]Preselection In Action post, I had an opportunity to do some field testing.  
So early last week, I went to a concert with two guy friends, one is 42 and the other is 48. I'm 49. We're all in great shape, and married. The show is headlined by a band popular in the 90's, but still putting out new music. The venue was a 5,000 seat amphitheater, and the median age of the crowd was probably 23.  
So I'm hanging with my buddies and looking around at the girls to possibly play a little catch-and-release. My friends don't seem interested in talking to any girls. So I keep wandering off, checking out the girls and making eye contact with a few. On the night, I think I got about 5 IOIs, hit on by a gay dude, danced with a cute little blond sitting behind me, and had a chunky HB5 chasing me around.

  Fast forward a couple of nights, and one of country music's biggest acts is in town. My wife doesn't want to go, so I invited her sister,who is 32. So me and SIL tailgate prior to the show in the parking lot.

  Now, this venue is 20,000 seats, so I'm guesstimating that I can just multiply the interest shown on the previous night by 4, and I'll end up with some proportional girl attention. The median age of the girls at this show is probably 30.

  Man, was I wrong!

  Tailgating, girls are coming by right and left, locking eyes with me, saying hey to me. A 40-something is all up in my face touching me, which leads to meeting a couple more (and younger) girls. And this is just the parking lot prior to the show.

  SIL and I take a few pics for Facebook, then we're off to the show. We get some good lawn seats and the headliners come out. Some dude and his girl come by, dude seems fairly alpha and his girl is hot. Dude starts dancing with SIL, who's enjoying it. So I grab his girl and startdancing. Dude rushes over and grabs his girl and drags her off into the crowd. OK, that was no alpha. SIL and I high-five and laugh. As the night goes on, I dance with SIL some, which leads to other girls coming up and dancing with me, then disappearing. Its a revolving door of young girls, lost count.

  I get home, my wife is waiting up for me, questioning me about the show. I tell her "I don't kiss and tell", then head for the shower. And you can guess how my night went from there.

  Point is, preselection is incredibly powerful. Granted, I wasn't really trying to meet girls, other than being a fun flirtatious guy. But the difference between 3 dudes hanging out, and a guy with a girl hanging out. Exponential.