Does player movement speed up mob spawners?

I have a friend that claims the faster you move around a mob spawner, the faster the mobs spawn. He likes to build powered rails near the spawner and ride a minecart in a loop. This is to increase the spawn rate, supposedly to several times as fast.

I was unable to find any credible source that mentions this. Is this in fact true, or is he misguided?

Solution 1:

I would say misguided. Check out the algorithm provided by the Minecraft wiki:

every spawn cycle (every randInt(200,799) ticks when a player is within
17 blocks of the spawner),
loop 4 times {
    if there are 6 or more of the mob type in the 17x9x17 area around the spawner,
       skip this spawn cycle
    calculate spawnerX = X coordinate of center of spawner - 0.5
    calculate spawnerY = Y coordinate of center of spawner - 0.5
    calculate spawnerZ = Z coordinate of center of spawner - 0.5
    calculate x coordinate of mob = spawnerX + (randDouble() - randDouble()) * 4,
        randDouble being a random number between 0 and 1
    calculate y coordinate of mob = spawnerY + a random integer between -1 and 1
    calculate z coordinate of mob = spawnerZ + (randDouble() - randDouble()) * 4,
        randDouble being a random number between 0 and 1
    if all of the conditions specific to the mob type are met, spawn the mob {
      chicken, cow, mooshroom, pig, sheep, wolf:
            block below spawning block is grass
            spawning block has a light level of 9 or higher

      ocelot:
            pass a 2/3 random test
            block below spawning block is grass or leaves
            on layer 63 or higher

      creeper, enderman, skeleton, spider, cave spider, zombie:
            light level 7 or less

      blaze:
            light level 11 or less

      silverfish:
            light level 11 or less, or on Stone blocks
            no players within 5 blocks

      slime:
            difficulty is not set to peaceful or slime size is small 
            either:
                    spawn block y coordinate is less than 40
                    the chunk containing the spawn block is a slime chunk (1 in 10 chance)
                    pass a 1 in 10 random test
            or:
                    swamp biome, layer 51 through 69, light level 7 or less

      ghast:
            pass a 1 in 20 random test

      squid:
            must not collide with any other entities
            must be in layer 46-62

      giant:
            light level 7 or less
            light level 8 or more
            (since these conditions can't be true simultaneously, giant spawners don't work)

      all except squid and slimes:
            must not collide with any blocks or other entities
            must not collide with water or lava
    }
}
if all 4 mobs failed to spawn, repeat on the next tick

Note that it has nothing about player speed in it.