Willow Creek, Saddleback, mega-churches REQUIRE tithing for membership??

I ran across this in Wikipedia today and was *stunned*:

There has also been much controversy with the introduction of "membership covenants" in many evangelical churches in North America, spearheaded by many mega-churches. These covenants, such as those introduced at the Willow Creek and Saddleback mega-churches, require giving 10% to that church as a condition of membership. Prospective members must sign off on a contract and are interviewed regarding their lifestyle, including tithing.

I realize that Wikipedia is not an unbiased resource. If you are a Willow Creek, Saddleback or mega-church member, I would appreciate any information that would either confirm or deny this.

Thanks.