You'd use an awful lot of super glue, plus you would have to clean off any existing adhesive off the back of the little strips of lead, and I'm not sure how effective super glue is on this anyway.
Sometimes you do come across leaded glass where the lead hasn't been stuck on very well, as Roger said, inform the customer about the state of the lead and tread very carefully when cleaning the windows.
Trad or WFP it is a pane for both methods if you have loose lead strips.
Ian