Is it bad practice to prevent jump links from cluttering browser history?

I'm developing a website with rather long pages, where the user can click on hyperlinks to scroll up/down to elements of interest. This scrolling is done smoothly (using jQuery), to help maintain positional awareness and to indicate to the user that they remain on the same page.

After the scrolling animation is over, a return false statement prevents the default action of the <a href="#section"> hyperlink. In other words, the url doesn't change from www.example.com/page to www.example.com/page#section as it would otherwise do.

Personally, I prefer it this way. I find it cumbersome to press the back button several times to go to the previous page. But is it considered bad practice to prevent the default (and hence expected) behaviour? Does it matter whether this scrolling is instantaneous or animated?

Thanks.