According to this article, while the window for unlimited donations for the recall closed on March 30, Walker has continued to collect -- more than $1 million. The article, by the Money and Politics Project, on how serious this is, or if it is more of an accounting issue.
Note that it discusses the origins of the unlimited donations law. It took place in 1987 and was backed by the state Elections Board, which deemed it "not significant."
At the time, the change was seen as helping state Sen. Gary George, a Democrat who racked up debt fighting a recall. It passed as part of that year's state budget, with bipartisan support, including from a Democratic assemblyman named Tom Barrett.
What that statement doesn't mention is that George did not end up facing a recall in 1987 (for his support of Ronald Reagan). However, he faced one in 2003, and was kicked out of office.