A complete rune page will give anywhere between 500-1300 or so worth of stats (typical starting rune page for adc/jungle for ex)
9.6 AD : equivalent to a longsword @ 360G
12.5 AS : going by dagger pricing 375G
12.5 MR : going by NMM 250G or CDR @ 395G worth of stats
10 Armor: going by Cloth Armor 200G
= 1185 Gold worth of stats at start of game NOT taking masteries into account
This means that without even choosing the most efficient runes gold/stat wise the Summoner with the MOST experience is given the equivalent of an early game triple kill, including first blood
If the player is even remotely competent that advantage will dominate his opponent so completely the only options will be to cower (and get raged at by team mates) or to get killed (and get raged at by team mates)
It's the only situation that is actually mitigated by smurfs as sometimes there are champs on the team that are skilled enough to still win or NOT lose under heavy disadvantage... however you likely would get matched up against level 30's because of those same smurfs boosting the mmr rating of the team astronomically.