Leave them be. If they don't know they need to set lineups, it's their problem. Also, you don't want to be making lineup decisions for people..."I would have played (insert last round pick who blows up in Week 1) instead of (insert injured 1st round pick)."
If anything, send an email to everyone as a reminder to set lineups.
"I'm normally not a praying man, but if you're up there, please save me Superman."
- Homer J. Simpson