Unlike Apple’s iTunes Preview website, which allows users to browse for apps on the web but then directs them to iTunes to securely complete their purchase, Google’s new web-based Android Market allows users to select and buy apps directly on the web site and then have the apps remotely installed on their device, something that is touted as a unique feature. [but...]

What if somebody else installs an app on your account?

ZDNet

If you use weak passwords your life will be hell no matter what online services you use. That's not a problem with the service its a problem with the user.

Unlike Apple's iTunes, if you uninstall apps from the Android Market within a certain period (I think 3 days) you get your money back automatically and without having to ask :-)