I doubt it will impact the outcome of your meeting one way or the other, but speaking as a guy who might happen to pass you on the street, or sit next to you on the bus, seductive clothing is always appreciated
LIQUIDS
As for the incident, I am sure you know that sensitive electronic equipment does not respond well to immersion. Practically speaking, I recommend you do what I do: keep liquids and foods as far away as possible from your computer. The only place liquid gets even remotely close to my computer is at the coffee shop, and even then, I have stuff in between the drink and the computer to mitigate the damage. I never eat near the computer. So far, I've avoided disaster. It is a pain sometimes, but I think it is worth it
INSURANCE
Poor students, in particular, need to look into renter's insurance. It is really inexpensive and will give you peace of mind.
THE GENIUS BAR
honesty is the best policy. No point in mucking things up. I'm sure they've had lots and lots of experience with liquid destruction, and wouldn't believe a tall tale anyways.
NEW COMPUTER
I have a new MBP 13"/8GB and I am quite pleased with it. From what you said, it looks like we do similar stuff. If you don't mind the weight and the extra money, the 15" would (of course) be the safest bet.
GOOD LUCK!