I don't get it: what is preventing people from starting mining "right now" instead of waiting for a specified time? Assuming they don't care about forking before even starting, OFC.
Every blockchain (coin) has a genesis block, that must be mined first before other blocks can be mined for the coin.
The genesis block is mined by the coin author before he releases the code. Mining without the genesis block doesn't generate valid blocks for that block chain.
Therefore mining is impossible before the code is released with the genesis block.
