Usually you will have 2 rules and 2 groups.
UAG group block include "domain users and local" exclude "exclude group" assigned to rule "block everything".
UAG group monitor include "exclude group" assigned to rule "monitor everything".
The issue you are asking about would come in where you have a group assigned to both a monitor and a block rule as above set to include (include exclude group in example a and b). In this case, the "block" feature will override the less aggressive "monitor" feature.