I bring my own tequilla as well when I go to Thailand because I can't stand what is there and I'm fond of premium tequilla. I have never just brought in only what they say I can. I figure if they find it they can have it and if not I'm set for my typical 3 month duration of a stay. Several mamasans I visit are always happy when I bring in a bottle to share with them.
I put this in my checked in luggage and wrap it up in bubble wrap to prevent breakage. Sofar it has worked everytime and never had a problem with customs thou I guess the odds are there. lol even more so now.
/e waves to the BM that is a customs agent..