That ID is invalid - names and IDs must start with a letter.
In W3C conforming browsers, if a label has no 'for' attribute, it is
associated with its contents.
"for = idref [CS]
"This attribute explicitly associates the label being defined with
another control. When present, the value of this attribute must be
the same as the value of the id attribute of some other control in
the same document. When absent, the label being defined is
associated with the element's contents."
However, IE does not conform in regard to the last statement.