The problem caused by the country list spam described in MBS-12537 applies to the normal (advanced) search as well.

If one searches for a single release country the results will also contain releases where the specified country is just one of hundreds. Or if one wanted to search for releases released in a specific set of countries, e.g. DACH, the results will also contain much more than desired.

There seems no way to omit country list spam results other than explicitly excluding each of them in the release country field.

Another noteworthy issue largely caused by the country list spam is the decreased search performance whenever there are results with many release events. See MBS-12536