I think there is a need for some built-in protection in Knoppix 6.7
to prevent the ruination of LiveUSBs that have been given a task that
turns out to be catastrophic.

What I have in mind is the bad result which occurs after starting a
download that proves ultimately too large for the LiveUSB to accommodate.
This ultimately fails, but also renders the LiveUSB inoperable without
extensive repairs or re-installation.

Couldn't there be some built-in surveillance to monitor for this
condition and head it off with some timely warning or corrective action?

Training the operator and/or using a larger USB are not solutions of interest.