The Awkward Time Bomb

Have you ever been in a situation where you know something very awkward is about to happen and you have no way of stopping the inevitable disaster? Its like a steam engine careening out of control and your standing on the tracks hoping to stop it with your bare hands... not very pretty

So, Mr. Life-Ninja date guy aka David called me on Wednesday to say hi and ask if I was going country swing dancing in Mesa that night. I told him that I appreciated his call but already had plans but would be there next week. We had a nice chat and since both of us were busy we decided we'd hold off doing another date until after this weekend. Since he had finals and I was moving it would make sense to hold off on things until Wednesday

Well, another guy put the moves on me and the conversation goes as follows.
"Hey Jill, you like Lindy hop Swing Dancing right?"
"Yeah"
"How about Country Swing Dancing? Do you know any country swing?"
"Yeah, I know some."
"Do you want to go Country Swing Dancing with me this Wednesday?"

Scenario 1: I could have said no. However, would I go on to explain that I have plans to meet up with another guy there on a "not date"? Do I say I have other plans and then show up only to have him discover my other plans were to go country dancing without him? Do I just blow both guys off and not go altogether?

Scenario 2: I could say sure. However, if David does show up (I'd be surprised if he doesn't) he'll be trying to ask me to dance while my date tries to dance exclusively with me and even if David is slick and manages to sweep me away I'd still likely need to carpool back with Robert and THAT would likely be awkward. I could also have a good time with Robert and nothing will matter that much except David may take me showing up with another guy as a total blowing him off....

I voted for scenario 2. I think "The Rules" would set that aside as the correct decision but the book doesn't seem to be everything I need. How about "How to disable Awkward Time Bombs"? I'd invest good money in that volume.