Yup. And Nostr has the same issue (date of an event can be in the past) but showing such a warning on Nostr is much harder.

-A relay might not record the time it received an event

-A relay might record the time it received an event but this information isn't exposed to clients

-A relay might record the time it received an event and this information is exposed to a given client but that client might not care

-A relay might record the time it received an event and this information is exposed to a given client and that client might care but it is unable to determine whether something suspicious is going on (are the event date and receipt date out of alignment for THAT relay only, perhaps because the event was rebroadcast, or is something else at play, need more data...)