Not true. You can search this subject here in the forum. Florida has a provision that if you are in the military and are buying a car outside the state of Fl, you do not have to pay Fl sales tax if you do not bring the car back into the state for 6 months. I bought a 2016 F-350 in California a few months ago and didn't pay the sales tax or other California fees. It is legitimate.
http://www.boe.ca.gov/pdf/pub52.pdf
I'll let you read the fine print but here's the rule in California printed verbatim.
"Please note: If at the time the contract to purchase the vehicle is made the service member arranges to take delivery of the vehicle in California, the service member will be considered to have made an independent determination to use the vehicle in California and tax will apply."
I'm not for sure how you got away with not paying sales tax (you may qualify for an exemption listed in the pub) but the California laws are very clear.
Bottom line, if you are stationed in California, buy a car in California, and use the car in California, you are subject to sales tax.
What that does mean for a Florida resident stationed in California who buys a car in California, uses it in California, and later registers it in Florida is that they pay tax to California at time of purchase and will not have to pay tax to Florida.
My father in law is an accountant for a tax attorney in California. After my initial responses I double checked with him and he verified what I've written here.
It may be different in other states (I.e, Oregon), I can't comment on those situations.
Bottom line, guys like
@EODDave may have avoided paying sales tax but according to the pubs and laws, it was an error and I wouldn't be surprised if California comes looking for that sales tax, with penalty, later on.