[quickben]

Because they collect them green and then ship them with ethylene so they just look 'red' ?

Ethylene: The Ripening Hormone

http://postharvest.tfrec.wsu.edu/pages/PC2000F

[vonmoltke]

Ethylene ripens the tomatoes, which is far more than making them "look red". That link does not address whether there is a difference between the end product of that accelerated ripening and a normal ripening.