Unmated female Corns occasionally lay clutches of infertile eggs. Usually when females ovulate and there is no fertilisation, the ova will be reabsorbed. But now and again you do get them developing and this results in a clutche of infertile eggs.
I guess it isn't ideal as it uses physical resources for no reason. However, there's no way of stopping it short of getting a "contraceptive" jab from the vet that stops them ovulating in the first place - I had this done for an old and frail female of mine who wouldn't stop laying slugs each year (can't remember the name of the drug but it's more commonly used to stop birds laying infertile eggs).
I've seen the production of infertile clutches being related to keeping adult females together, but as yet this is only anecdotal unless someone out there has found a formal study?