So you have a gig with a lot of functionally similar scenes, and they all have the same recall filter settings. Say it’s a theatre gig with 100 or so scenes which block everything except the input channels for the casts’ mics, which are totally “allowed”. Mixed in with these are other scenes with different purposes, (band, sound effects etc.) with different recall filter settings.
Lets say once the show is programmed and running you need to change the recall filter for all 100 of the cast scenes (for example to block recall of the PEQ because mic positions aren’t what they should be and it needs to change and stay changed). Unless I’m missing something the only way to do this “properly” is to go to one hundred individual scenes and perform a repetitive identical edit to all their filters. If it has to happen IMMEDIATELY you can go to the global scene safe and block it there, but this will block it from the non-cast scenes too, which will be a problem. If you have a scenario where you need to ALLOW something to all those scenes that is blocked in the individual scene filters there is no way at all to do this, even globally, even if a global change were an acceptable compromise.
A similar situation would arise with multi band events where you have changeover scenes which all do the same type of thing (but with unique stored contents), and other scenes for different songs and effects which all have unique filters according to their various purposes. You to need change something from the changeover recall settings last minute, but you can’t do this without going to each and every changeover scene and changing it there. Blocking something globally will screw up your “mid-song effects routing” scenes and unblocking globally doesn’t exist unless the initial block was set globally.
I propose a solution, (1) “reference recall filters” or (2) “assignable sub-global scene safes” depending on the implementation:
(1) This is a recall filter to which scenes can be referenced, via a “use profile from” box in each scene filter page. This is a live synchronization so changing a reference setting immediately imparts the change on all scenes which reference it. This would “grey out” and replace the scene’s own recall filter so there is no confusion about which menu is responsible for a setting. The reference could be set to only read certain parameters to the scenes referencing it, local filter data would be used for everything else. The “Block / Allow” box in the individual scene filter would be turned a special colour (not red) when it’s status was being set from an external source. This will allow unblocking of a filter across multiple scenes by dictating an “allow” from a reference they are all assigned to.
(2) This works the same as a normal global safe but can be assigned to on a per-scene basis and is a hierarchy level below the main Global Scene Safe. I’d envision blocking a lot less in the overall global filter which removes some “gotcha’s” but would still allow a large group of channels to have safes applied to them en masse. This is much simpler but leaves the familiar problems of not being able to “mass unblock” if blocks are set at the individual scene level.
Think of option 1 as being like a DCA (but dealing with absolute “Block” / “Allow”, so different) and option 2 as being like a subgroup.
With the implementation of option 2, option 1 is less likely to be necessary. Locally blocking the same thing in multiple scenes (and hence the need to mass unblock) is only done because the Global Safe, while it has it’s important uses, is too absolute for many scenarios. Option 2 on it’s own would mean that those blocks could be applied (and cleared) at a sub-global level, maybe making the extra complexity of option 1 redundant.
This undoubtedly needs more discussion but I think it would really solve some problems if the potential for confusion can be avoided.
If nothing else, please add a library item for recall filter settings. This would allow the new setting to be stored and manually added to each scene more quickly.
Thanks for reading all this, 
Chris