I'm sorry, I feel the need for deception is unnecessary. The bigger deal you make out of it, the bigger deal THEY make out of it. There are SOOO many views on this. This is just how WE have chosen to handle the issue:
My Husband and I would rather our daughters (now 18 and 21) know their limits with us present, than to be out with friends and flip coins for a driver, or take nominations on the one who seems "the least drunk".
My husband and I are not big "drinkers", but have an ocassional drink with supper or in a social setting. Since our girls have been over 13/14, we've never made having a drink a big deal. Our older daughter was never really interested, but our younger one is a little (a LOT) more adventuresome. So, she's welcome to order a mixed drink if I'm having one.
We are extremely up for discussion with her about alcohol or anything else, and she knows it. She's NEVER had to sneak around to test the waters. Only once has she had to call for a safe ride, and I picked all three up and delivered them home. I did not chastise her, as I was just grateful she'd had the forsight to hide the friends' keys and make the call. Later, we did have a discussion about the party, and how the situation *should* have gone down... and *could* have gone down...
After a only few times of over indulging she's decided that it makes you look really stupid, and makes you feel REALLY bad later. So, as she's decided it's a LOT more fun to watch everyone ELSE make themselves look stupid, she OFFERS to be the designated driver whenever she and friends to go a party...etc. That way, we don't worry about her, she doesn't worry about her friends, and doesn't get teased for being "a prude" or "party pooper". Her truck will accomodate 5 plus her, so many times friends will offer to pay her diesel and any other charges if she'll just drive.
She'll still sip on a Margarita, or such with us, but it's not something that she does often, or over her safe zone. She says she's SO over the big deal of alcohol.