Initial Summary:
provide admin option to NOT automatically REbuild initrds for previously
installed kernels

From bug 1189772, where this request has already had some discussion about how
it might be implemented:
[quote]
> (In reply to Martin Wilck from comment #7)
>> (In reply to Felix Miata from comment #6)
>> IMO, openSUSE should also have an admin option not to rebuild, regardless of
>> use case. What I do on openSUSE is set immutable flag on initrds. It doesn't
>> stop the rebuild waste of CPU cycles and SSD writes, but I get the result I
>> want.

> Fair enough. Please open a feature request.
[/quote]:

On Debians there's been this to implement admin preference since forever:
# cat /etc/initramfs-tools/update-initramfs.conf
#
# Configuration file for update-initramfs(8)
#

#
# update_initramfs [ yes | all | no ]
#
# Default is yes
# If set to all update-initramfs will update all initramfs
# If set to no disables any update to initramfs beside kernel upgrade

update_initramfs=no

#
# backup_initramfs [ yes | no ]
#
# Default is no
# If set to no leaves no .bak backup files.

backup_initramfs=no