This would be the turning point for the hashrate and obviousely the value of the BTC.
Sad but true
Don't know what you mean by "scraping" the web, but wallet.dat files are not accessible on the public internet. You usually have to hack into someone's system in order to steal a wallet. Or you have to be a corrupt employee of a cloud storage/ web hosting service.
https://www.google.com/#hl=en&safe=off&sclient=psy-ab&q=intitle:index.of++-html+-htm+-php+-asp+-txt+-pls+wallet.dat&oq=intitle:index.of++-html+-htm+-php+-asp+-txt+-pls+wallet.dat&gs_l=hp.3...3387.3387.5.3947.1.1.0.0.0.0.48.48.1.1.0.les%3Befrsh..0.0...1.EMtX7-UHH2c&pbx=1&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.&fp=66a4114761f62281&biw=1280&bih=702
or it can be done with google
I tried it but my Google-fu wasn't high enough to come up with the query, this is awesome.
So snatching wallet.dat's is plausible. If you think nobody would ever put out a real wallet like this, consider that all sorts of sensitive info gets accidentally published and indexed by Google and is searchable with clever queries like this.