:SNIP: i dont get what you mean? 'always' installed?
Modifications to operating code of phpBB is what MODs are all about. Some MODs require that actual database tables or fields be added, modified, or otherwise changed. The MODs that change the physical structure of the database are the ones that I am talking about.
Once database structure is changed, the calls made to the new structure can cause improper database functionality. Leaving orphaned fields and tables is never a good idea. If a certain MOD adds, changes, or otherwise modifies the operating database itself, that MOD must remain a functional part of any 'upgrades' made to the front end that uses the information stored in the database itself. The only alternative is to discard existing data and start from scratch with a clean install. (Not
an option for those running 'real life' databases used by hundreds or thousands of users.)
It would be nice if there were some sort of a notice that showed MODs that change physical database structure. This would be of particular interest to those of us who track MODders who maintain their code with updates. I will not install any MOD if the MODder has no history of upgrading his or her code as phpBB progresses. Being forced to start from scratch is why I switched from vBulletin to phpBB in the first place.