"Service monitoring rules" vs "Enforced services"

Exactly.


Not sure yet, but the same simplification seems to apply to these:

Enable/disable active checks for services
Enable/disable passive checks for services

Here may be the rule option should have three values:

Apply to all checks
Apply to active checks only
Apply to passive checks only


I asked about another similar possible simplification for check periods here:

Check periods: “for active services” vs for “passive Checkmk services”