Initial values for widows and orphans

I just added support for 'widows' and 'orphans' to WebKit [1].

Unfortunately, in order to not break existing content, I couldn't use the specified initial values of 2. Instead I had to go against the spec and accept a value of 'auto' and have that be the initial value. In WebKit, this means do nothing (do not try to avoid widows or orphans).

What was the reasoning behind having such initial values? [2] [3]

[1] http://trac.webkit.org/changeset/137200
[2] http://www.w3.org/TR/css3-page/#breaks-inside
[3] http://dev.w3.org/csswg/css3-page/#breaks-inside