Naaaah, really edge case, which also should be handled differently (imho). If someone has limited/poor/no internet connection, then one should use media with most (all?) packages.
Next, after succesfull install updates should be applied using local repository (eg. apt-cacher) which addresses poor network connectivity.
For this reason we have following check in 41cdset generator script:
<snip>
if [ ! -e /cdrom/.disk/cd_type ] || [ ! -e /var/lib/install-cd.id ]; then
exit 0
fi
# Various different image types look different here:
#
# Image Type cd_type
###################################################
# netinst "not_complete"
# full CD sets (default desktop) "full_cd"
# desktop-specific CD images "full_cd/single"
# DVD "dvd"
# bluray "bluray"
# multi-arch CD/DVD "not_complete"
# live "live"
#
# It can make sense to offer to scan more media here in most cases,
# but... on live or blu-ray it's unlikely to help; the
# desktop-specific image is designed specifically to work with only a
# single image. Hopefully the following makes sense.
#
# Images written to USB pen drives still need better support
# too... :-(
cd_type=$(cat /cdrom/.disk/cd_type)
<snip>
Warm regards,
Jerzy