You do not get them if you are admitted as an AC member. You get them if you are admitted for QC reciprocal admission, elite status and class of service per the applicable lounge access guidelines.

Therefore, if you are both an AC member and PLT/EXP traveling overseas, present your boarding pass rather than your AC card if you care about this. Presenting both will not get you anything extra.

There is apparently no consistency as regards getting one or two per person, but whenever I've been given one and wanted two, asking for a second has worked. (I don't drink much, but a glass of wine and a bottle of water for the plane isn't exactly over-the-top drunken behavior.)

I concur with the advice to tip anyhow. It's not the bartender's fault that you don't have to pay cash for the drink.