What you use has no bearing. Your name is either drawn or it isn't. Or, in the case of an instant win you are the first to enter on or after the seeded time, or you aren't. Use Google Autofill or Roboform, it makes no difference.
That said, I've won using Google Autofill, although I won using IE, not Chrome.
I switched to Roboform after years of using Autofill because Roboform is a better program. Roboform fills out forms more completely than Autofill. It's been several years since I used Autofill, but I don't recall it asking for a birthday during the setup process. Therefore, it couldn't fill in that field on a sweeps entry form. There are other fields for some sweeps that sometimes Autofill wouldn't complete, yet Roboform will.
Autofill is a small program for Google. I don't think they've spent the time or resources to fully develop it.
