Surely a two tier system already exists? We already have a system with us Britannia guests the lowly option compared to Grill guests.
If packages were brought in there would be no obvious distinction between guests. In the same way currently while onboard you can have no idea who has bought an internet package, who is paying service charges and who has had them taken off. You would not know who had bought a package so how could that bring about a new two tier system?
I would welcome the introduction of packages. I like to start my cruise knowing all the essentials are taken care of. It would be good to have choice. Those who do not want a package could choose not to have them.
