Форумы / Cotonti / Core Labs / Ideas / Groups without rights table

In the LDU groups was fictitiously, user can add his own private groups. were open groups
In Seditio it was removed. Every seditio group was it own rights. I think some times it is not good. For example on my site: more 150 categories, 20 sections in the forum, 60 plugins, 20 groups, although the rights table only different in 5 groups. Calculate:
20x230-5x230 = 4600-1150 = 3450 blank SQL entries, which are not needed in the database, which will not be used.
Proposal:
Add additional field to the database "group type": normal, "rightsfree" or group that created by users

Admins, Developers, Designers - please write your opinion