The Zentradi would probably shoot you for being in their way anyways....In M7, the fleet stopped the Meltrans and looked what happened...The Macross-design apparently proved viable for short-range and exploration/research missions so why not use the design. It would be almost 20 years till the New-Macross class came which would satisfy the power-house of the Macross-class and be viable for long-range missions like the Megaroads.