Several friends of mine, who are also agents, have flat out said they either will not sell Carnival or they will certainly try to steer clients away from them.
While past guests who have traveled Carnival before know what they're getting and are certain they'll want to do it again, new cruisers are often not as informed and can be influenced as to what cruise lines to consider in their quest for the perfect cruise.
Personally, I'm not that type of agent, but I know many who are. This is why I always tell people to stay away from agents who are always "recommending" things.
There are three reasons why an agent recommends;
1) It may be the only thing they know and have no personal experience to compare it against others.
2) They may have liked it, but we're all different people; what one person loves, another will hate.
3) That cruise line or resort pays them a higher commission.
In other words, when an agent recommends, it's usually not in the best interest of the client.
I believe an agent's job is to provide as much unbiased information as possible so a client can make an informed decision to select a cruise or vacation that is right for them based on their requirements, lifestyle, and budget. That's not to say I won't make some suggestions based on those items to help them narrow down the multitude of choices, but when people recommend, they are, in effect, steering someone where they may not want to go. That's why it's always best to do alot of homework, read the reviews, and ask alot of questions.
Now, with all that said, there are obviously alot of agents who just want to make a buck as quickly as possible and will do nothing but constantly recommend. I've seen it happen first hand. I once watched an elderly couple talk to an agent about a cruise and the only cruise line the agent mentioned during the entire conversation was Carnival, when there were at least 4 other cruise lines doing the exact same itinerary and all were much better suited to what the client wanted. When I got home, I did some research out of curiosity and found Carnival was offering an extra $50 commission for this particular cruise. It was obvious the agent had only one thing in mind and that was definitely not in the client's best interest.
Sorry, didn't mean to get off the subject, but the bottom line is that while I know for a fact some agents will definitely try to steer clients away from Carnival, a good agent should really listen to what the client wants and provide them all the options available irregardless of how they feel about a particular cruise line.
I have no doubt this will impact sales, but to what degree at this time is unknown. But if Carnival keeps it up, they will definitely find themselves in a quandary with agents and in the long run, everyone will suffer because of it, especially the passengers.
Quite frankly, if people book directly with the cruise line and a problem occurs, who do you think the cruise line represents? It's certainly not the passenger. Whereas when someone books with an agent, they have an advocate on their side and will fight the battles that need to be fought when something happens. Plus, they have information about all the cruise lines, not just that one the passenger is talking to. So they can either talk to each cruise line or talk to one agent. Then there's always the information about the ships, itineraries, and all the questions passengers have.
There was a report once put out that more than 95% of the time when you call the cruise line or a large online site that the person you're talking to works in a call center, has worked for the company less than 6 months, is not a certified travel agent, and has never been on a cruise or to any of the ports. So their knowledge is limited to selling and that's all they can do. This is why CLIA (the Cruise Lines International Association that we all belong to) states that approximately 90% of all cruises are booked using an agent. People recognize the importance as well as the benefit in using someone who has substantial knowledge and experience.
If Carnival chooses to alienate agents, which represent the majority of how their cruises are booked, I believe in the end it will have a huge impact. They will get so overwhelmed that passengers will get extremely frustrated and go elsewhere. Their customer service is rather poor now, I can only imagine how bad it will get should they continue down this road.
They actually tried the same strategy years ago and realized it was a huge mistake. I have no doubt eventually this, too, will be realized as a very bad idea.
Didn't mean for the answer to your question to be so long and detailed, but as you can see, this is a major issue and tremendously important because it affects everyone involved.