Ah yeah, good point! What happens if I'm using Primal but I want to follow someone who is using one of these lockbox/zapbox relays for their special content? I'm happy to zap them the threshold. But how does the special content get from that zapbox relay to Primal's aggregator relay so I can see it in Primal? Didn't think about that.
Primal is not going to be the app to use if you want ANY kind of custom read relays. They ONLY have their caching relay for folks to read from, and I don't see them changing that model any time soon.
To achieve what you are looking for, I would recommend only reading from and writing to web-of-trust relays. Even better if you can run your own. But to have custom relays to read from, you're going to need to use a client that actually cares what you have set for your read relays. Not Primal.
There's a list of web-of-trust relays here: https://github.com/bitvora/wot-relay
I also run one at wss://wot.brightbolt.net.
Another option would be to use Coracle.social and crank your minimum web-of-trust score for seeing notes up to 3 or so. Jerks will still be able to see and interact with your notes, but Coracle will automatically hide whatever they say, because they aren't within your web-of-trust.
Discussion
Yeah, it doesn't. I expect Primal is not able to pull those in.
Hmm yeah. Primal couldn't really zap the threshold themselves and then use their own access to the lockbox to grab the events and copy them over to their aggregator relay, as that'd make those events viewable by anyone (yikes). And if Primal tried to replicate the lockbox filtering in a quasi-sense on their end (purely client-side) then what's the point?
Plus I suppose the lockbox owner could put up a robots.txt style don't-broadcast-this-stuff notice, adding legal concerns on top.
If this lockbox takes hold it makes you wonder if aggregation can scale.