WB Yeats back on the Dublin-Cherbourg run from tomorrow. I'd assume that Irish Ferries expect some form of tourist travel to be allowed in the near future.Summer season is underway if people choose not to travel they probably will not be entitled to a refund as the full service is now being offered.
This is where things get complicated. The Department of Foreign
affairs is still advising against non-essential travel to France, yet the service is being offered so Irish Ferries would be fulfilling the Sales of Goods act.
I imagine if you choose not to travel, your only option would be to claim under Travel Insurance (usually if the DFA advise not to travel, it's covered).
Ferry operators are in a tough place here (as are airlines). It's costing them a fortune with refunds and laying up equipment, but if they don't show passengers some flexibility, they are going to lose a lot of goodwill.