Hawk
You know, that theory does make some sense, but as I've learned about how much women spend on cosmetics, shoes, and feminine hygiene products, I feel like the burden of cost starts to run even between genders. It sounds like it's kind of expensive to be a girl.
I also wear shoes. Just because I don't blow my paycheck on them...
Girls seem to buy alot of shoes because they like to accesorize more than they do in order to look good on a date. Men have haircare products and cologne too. You make it sound like the meal is the only money we sink into a date, whereas they HAVE TO blow all this extra money on things to make them more aestheticly pleasing that guys don't.
It also depends where they dropped the wallets. I imagine a small town in the northeast would have a better return rate then the bronx. It would also probably be affected by the financial status of the person who found the wallet.
100 wallets just isn't enough to test the theory, there are just too many mitigating factors. You'd need thousands. And you'd need to categorize every enviromental cause that could affect the outcome.
Generally though, I think the precent of honest ladies would still be better than the precent of honest men. But then, I'm a big fan of the ladies.