While the idea that robo reviewers should be banned for longer is worth taking into account, please note the number of disputed auditsdisputed audits.
As currently implemented, it's almost impossible (for reviewers that don't "cheat" using enhancements detecting audits) not to fail an audit from time to time! Implementing your request literally would eventually permanently ban all reviewers.
The ban should be increased only if the reviewer continues with failed audits after previous ban is lifted. Good audit history before meeting new review ban should not result in more severy ban.
Such implementations would target only those reviewers, who show no improvement and tend to robo-review. The reviewers that get a ban occasionally because audits are chosen blindly should not be punished.