Snapshot recovery

All, Apologies if this has been asked before but I can't seem to find a definitive answer to this scenario.

If a customer decides to create hourly snapshots of a volume, so we have a structure like -

Prod Vol - snap1 - snap2 -snap3 -snap4

If they decide to rollback Prod Vol to (for example) snap2, do the previous and subsequent snaps remain as snaps of the original Prod Vol, or do they become snaps on the restored Prod Vol( which was snap2)?

This question is being asked because the customer can envisage a scenario whereby they might encounter a corruption on the original Prod Vol but not know which snap will allow then to roll back to a known good state but they are concerned that rolling back to a prvious snap may result in them over-writing and previous snaps.

Thanks in advance

Alan