If a woman you don’t know asks you out to coffee, do you assume it’s a lesbian date?

As a woman, if another woman you don’t really know were to approach you and say you seem interesting and ask you out to coffee, would you assume it’s a romantic/lesbian date, or just assume it’s friendly and platonic? Say for instance you’ve just seen her around a few times but don’t know her name or have any acquaintances in common.

Would you be open to saying yes, or find it unusual?