Without a doubt, salvation is assured for those who have performed Prapatti.
Perumal forgives the offense that one commits un-intentionally.
If we commit an offense intentionally then we have to do Prayaschita Prapatti or undergo the Lord’s punishment. The elders who had done Prapatti talk sternly to channelize the person properly and their intention is not to hurt others. So, it cannot be deemed as an offense.