Why are unregistered users allowed to post? This only creates a plethora of accounts who post a question and never come back to provide feedback or accept answers.
Allowing questions from unregistered users has been a feature of Stack Exchange (all the sites) since the very beginning and is not unique to Travel. A handful of sites require creating an account to ask, and I could perhaps interpret your question as a suggestion that Travel do the same.
You theorize that unregistered askers fail to provide feedback or accept answers, and though you don't say so I presume you mean that they do this more than registered users would. That's hard to prove: someone who registers when they don't have to will not behave the same way as someone who was made to register just to ask their question, so observing what today's registered users do isn't a good predictor of what would happen if we made people register.
However you should know that the system has been designed to work with non-responsive askers. If a question is unclear, it can be put on hold until the asker gives the required feedback. If that feedback never comes, the question can be deleted almost automatically. If other people happen to spot a word or two that enables them to understand a cryptic question, they can edit it into a clearer question. If the question is clear and useful as written, it can continue to provide value to future readers, and to attract answers that provide value to future readers, indefinitely. Accepting is less common on this and other not-code-related sites anyway, partly because selecting a single answer that works is not always possible.
For these reasons, I don't support any suggestion that Travel should require users to register before asking a question.
Here are the top 5 questions contributed by users who never came back to the site after asking (found using Data Explorer):
- Boss is asking for passport, but it has a stamp in it I don't want him to see. What to do?
- Took airline plane blanket by accident; didn't realize it was forbidden. What should I do?
- How to lift a lifetime ban from Canada due to marijuana?
- Are there any flights which permits a Sikh to carry a kirpan?
- Being separated from one's young children on a flight
As a moderator I'd much rather have these questions on the site than enforce registration, even if it means we have to deal with a lot of spam and unclear questions from unregistered users. Overall we've received 793 questions from unregistered users that received at least 5 upvotes, with a combined viewcount of 5,109,487 views.
Finally remember that StackExchange is not meant to assist individual users with their unique problems. It instead strives to create a database of questions that would be useful to millions of people around the world who share the same issues. Therefore it is pretty much irrelevant if OP ever comes back to the site or accepts the answer.
Allowing questions (and answers) from non registered users may have been a feature of Stack Exchange since the start.
That does not mean that it can not change and I am asking for change every time I discus it with people who might do anything about it.
The more the site gets known, the more spammers and trolls we get, on top of the usual clueless ships in the night who never even come in to read the replies and requests for more information.
I guess that in time registration before participation will become the norm, but for now the people that hold the power to change things do not feel it is needed yet.
So while I agree with the OP here, I can not give a positive 'will be soon' or 'will ever be' as it is not to me to change it.