Since we already know that the then-current regime in Israel claimed that Jesus had never been resurrected and that his disciples had spirited the body away, it's not beyond the realm of possibility in the decades before the destruction of Jerusalem that they constructed their very own tomb to point to as proof of their assertion.
It all does seem too very tidy and coincidental to find a whole family of peasants (at least just that generation of the family) with stone coffins listed by name, in one place, buried as wealthy people, and over 2000 years no one ever spoke or hinted of it. And in Jerusalem, many native people still casually acknowledge every place of any historical significance as if the events occurred last year.