Would the bondsman only lose 30%? From this discussion, they only have to post 30%, but the other 70% could become due when the terms of release are not met.

That's still a better deal for the bondsman, but it's also reasonable. If you don't show up for court, it doesn't seem likely that you'll show up to deposit the other 70%... But if you don't show up for court, the bondsman probably hasn't left, and they will be available to pay the rest of the bail amount.