A Tombstone in a signed log is not the same as "marking an entry as deleted", it's replacing an entry with something that contains enough data to maintain log i

A Tombstone in a signed log is not the same as "marking an entry as deleted", it's replacing an entry with something that contains enough data to maintain log integrity. E.g. "this tombstone replaces an object that had the hash XYZ". The problem that remains is that for everyone who doesn't follow the tombstoning request and keeps the old value, they can still "prove" that what they claim was the original value is correct because its signed, unless you do more complex stuff with non-repudiation constructions etc.