The rules seem to be fairly reasonable to me as a safeguard to the operations.
Many years ago in Abu Dhabi, a few ATCOs swapped shifts to facilitate a short vacation in the Far East. Unfortunately they got stranded abroad and we really struggled to keep things going. The result was that management changed the roster from AAMMNNSOOO to MANSO so that it was impossible to leave the country on your day off! Fortunately the change didn't last long because severe fatigue soon set in with the new roster.
I also remember one ATCO in Dubai who swapped shifts so that he worked fourteen nights in a row which gave him an extra two weeks leave at the start of his annual vacation! Couldn't happen now - could it?