After my post Google is your default search, that reported a new feature in Google Toolbar 4: a monitoring tool that blocks any attempt to replace Google with other search engine in Internet Explorer, but remains loaded even if it is disabled - Google has updated the toolbar. They removed the bug, so the monitoring tool can be disabled and they also changed the wording in the settings:
While Google insists that this feature was added to prevent malware to change the default search engine in the settings, I think Google wanted to counterattack the software from Yahoo or Microsoft that includes the option to change the search engine enabled by default (Google's software also does that). If you download Yahoo Messenger or Windows Live Messenger, and keep the default settings, you'll change the search engine to Yahoo or MSN. But what's so important about the search engine in IE? you'll ask. The major battle of the default search engine is for IE7, a browser that has a search box, unlike the previous versions.
"The main issue is that many users do not have security software that prevents their search settings from being changed without their consent. As more advanced browsers and browser features become available, search settings in IE will become increasingly important. The notifier enhances a user’s control over their internet browsing experience. If users want to keep Google as their search setting, we want it to be easy for them to do so," says Benjamin Lewis, Product Manager for Google Toolbar.