Comment 11 for bug 1845571

For the dell usecase, the expection is to "use free" or "wipe Ubuntu FOO and reinstall", meaning that only free space is used or an existing Ubuntu partition is wiped & reinstalled.

Meaning that the full device /dev/sdb (the install media) is not offered for install target.

The only time we do support wiping and installing ont hte full /dev/sdb which we booted from, is when casper was booted with toram option. In which case yes, it's expected to wipe the disk one booted from.