"What do you mean practically when you say they’re not meant to make use of it? They’re meant to fly Dublin-Paris-Manchester?" No - Simply that they're suppose

"What do you mean practically when you say they’re not meant to make use of it? They’re meant to fly Dublin-Paris-Manchester?" No - Simply that they're supposed to fulfill the entry requirements for non British or Irish folks, or risk arrest, prosecution, and being deported. That happened to some folks from Peru (I believe), who traveled to GB via Ireland, NI, then ferry to Scotland. Simply the CTA is misnamed, it is not a "travel area", that is simply an effect arising out of the reciprocal rights of British and Irish citizens in the other state.