its hard to say...almost impossible to say.it depends on the hydroponic shop....i might go back in there and pretend im going in to get info/seeds for cultivating strawberrys,carrots,or pumpkins.then pay for that with some cash.start a conversation with a clerk.i dont know though..i dont blame ya for bein paranoid though.if medical marijuana is illegal where you live,then i'd be a little more paranoid of usin a c.c. as payment,due to the fact the leo might be trying to have them work with them for info...but theres not much you can do now.minds as well just risk it and do what you spent your money to do.good luck-peace