"They" being who? The tech who installed the one from Lowes? Keystone? I don't think it matters since it is the faucet mfg who installs the restrictor.
See:
http://energy.ca.gov/2015publication...CMF-marked.pdf 1.8GPM maybe 2.2GPM if you're lucky.
As goes Kalifornia so goes the nation.......
I don't think anyone has a choice in whether you get a restrictor or not. Once it is yours you can do what you want.
Only in Kalifornia will the faucet police knock on your door and impound your faucet if you remove the restrictor. You will also get fined and some jail time. And your water will be turned off. You have been warned.
