Related was how the Navy used to recruit, was case of if they could pass you a coin (shilling iirc) you had taken the kings money and was duly obliged to serve.

What would happen is they would drop coins into unsuspecting drinks in the local taverns and the drinker would suddenly find himself drinking and then touching the coin onto his lips on the last drink (something like that). So to avoid this the trend was to have drinking tankards with a glass bottom, so the drinker could check he was not being press-ganged into the navy.

ok did quick google and wiki does more service to this than my memory:- https://en.wikipedia.org/wiki/King%27s_shilling