You should really do some digging into Walker, the governor in question here. Ask yourself why it is that the public sector unions that supported him are exempt from all of his new restrictions and limitations.
There's quite a few things criminally corrupt here.
I personally support leaving to deny quorum. If the other side refuses to respect the minority, then the minority has to do what is legally within it's power to protect its rights. In this situation, the ability to compel attendance absolutely does not mean that choosing not to attend is against the law.
For the record, if it were reversed, I'd support the GOP senators doing the same. As a moderate, I get really angry at the whole tyranny of the majority thing.
Meeting of legislature. SECTION 11. [As amended Nov.
1881 and April 1968] The legislature shall meet at the seat of
government at such time as shall be provided by law, unless convened
by the governor in special session, and when so convened
no business shall be transacted except as shall be necessary to
accomplish the special purposes for which it was convened.
[1880 J.R. 9S, 1881 J.R. 7A, 1881 c. 262, vote Nov. 1881; 1965
J.R. 57, 1967 J.R. 48, vote April 1968]
When the legislature is in session, legislators are required to be there. According to the constitution at least. But it's just their constitution, it's not like that's the law or anything.