Thats an old wives tale.
The pickup is in the bottom of the tank, so it will always be picking fuel from the bottom, regardless of how much is in.
Further to this, with the amount of fluid movement generated when going over bumps, up/down hill, around corners, braking etc, would mean any sediment would be in suspension.
Only after being stood for several hours would any gunk settle, and this would be picked up on the first turn of the key (everytime).
Also that’s why there’s a fuel filter.