you can mix them but IDs are the narrowest filter and only the IDs search is done because it wouldn't even matter if any other criteria matched if the ID doesn't match. in processing you just shortcut and only process IDs and check that first so it precedes the rest.

logically any ID criteria supersedes any other because in a filter, each field, ids, authors, tags, etc, has to have one match, so if you have 3 different top level fields in the req, then every result matches all three tests. if there is any IDs in there, then a match on one is a match on the whole group. the general policy that relays have is they just ignore the other fields. you *could* not-ignore them but then you get the side effect that unless the specified events with those IDs also have match on the others then they would be excluded, and probably the dumb client dev is wondering why when they ask for IDs they don't get all of them.

so, yeah, fuck those stupid people. give them the IDs and make anything in IDs mean IDs only. the opposite arrangement is illogical.