"The lack of a warranty disclaimer isn't an issue in practice;" There have in fact been developers sued (and they lost!) over this very issue in analogous situ

"The lack of a warranty disclaimer isn't an issue in practice;" There have in fact been developers sued (and they lost!) over this very issue in analogous situations, so i'm not sure why you say this. "my readme just says "WTFPL, no warranty". The vague rights grant isn't something I've seen as an issue in analogous situations in case law." I'm not sure where you looked. Judges have varied wildly in what they have done in analogous situations. We are nothing if not data driven. If we didn't have very good data that suggests it is an issue, we wouldn't care.