To answer directly, yes, but this needs to be detailed for a complete understanding. In my opinion, there are two aspects that must be considered
- Lax view on dishonesty
- what counts as dishonesty
There are some countries that have a more lazed view on dishonesty, one is my home country.
Cheating in an exam is always punished (not harshly though), but rarely looked upon by colleagues. Moreover, you usually have options to retake the exam if you were caught cheating and if you pass, you're at par with everyone else. But to really understand the phenomena, you need a little bit more context.
Where I come from, I had university classes where we had to memorize full lectures and all you had to do at the exam was to write the full lecture on paper. The whole exam was pointless, you didn't learn anything anyway, so if you could bypass the exam, it would mean that you managed to save some time that nobody gives you back. I even had a senile (literally, it's sad) professor who was giving sort of random grades, barely correlated with the number of pages you wrote and the graphs you made, without even reading what you wrote. Moreover, the study material was about techniques not in use for the past 20 years at least. If you take what I just said for granted, I think everyone would reach the conclusion that studying for this class in order to pass the exam is not only pointless, but the wrong approach, since the goal is to write as much as possible and draw some pretty, barely related graphs.
By now you probably think that the university I'm talking about must be some fake/scam university in an underdeveloped country. Again, you have to trust me, and I see how I am very hard to trust, but this university is considered a respectable university in a EU country.
To conclude this point, some countries have a more relaxed view on academic dishonesty, but things still go on, because the academic is pulled by other aspects of the society that work better. For example, I went through all this classes of this university and graduated, and this granted me a diploma that allowed me to join a masters programme at a world TOP 50 university, in another EU country. So basically, the good politics were good enough to join the Bologna system and EU, which allowed this backwards university to exist in order to provide diplomas for people for which diplomas are vital for their future. Even though I had such a horrific background, I performed well on my masters, at least at par and sometimes even better than students with good backgrounds.
Now going to the second point. Not everything that would be considered academic dishonesty in western countries is considered dishonesty in other countries. For example, a failure to cite half a page of verbatim copy in a PhD thesis in a western countries would be academically fatal. Where I come from, these things get relativized to other issues that there are in the countries, and I would add, for a good reason. It's easy to see plagiarism as the worst sin ever if in your bubble it is indeed the worst sin ever. But when one public person is accused of embezzling millions or even tens of millions of dollars, and then the accused accuses the accuser that he copied some paragraphs in his PhD thesis, it is easy to see how the public opinion doesn't care about, literally, some copied words on a piece of paper. Then these things work as examples for the public, and the conclusion is: it is fine to plagiarize, but it is not fine to steal millions of dollars from public money. Both are bad, but at scale, the first is negligible and can be approximated with "not bad".
I don't want my examples to be used as some sort of reasoning to discriminate people that come from countries with different ethical standards, because everything that someone from these countries does, because he developed different cultural ethical standards, a person from a western country can do as well, just because he doesn't hold to his cultural ethical standards.
Considering the original question, and my cultural background, I think it might be valuable for the answer of this question, my answer to the original question.
I personally consider that it is not unethical if, the person that was asked to write a recommendation letter (the professor), does not mention the incident, if he truly recommends the student for the PhD position. Moreover, I consider it unethical to include negative comments in a recommendation letter. My reasoning for this is that a recommendation letter is just that, a recommendation letter. It should only include why you recommend someone, the fact that you recommend that person is already clear from the existence of the letter. A recommendation letter is not a summary report on previous activity. The moment you include negative comments in a recommendation letter, you start being deceiving towards the person that you are recommending, by giving false hopes, and also towards the committee to which the letter is addressed, by recommending someone you do not truly believe it should be recommended.
In my opinion, if someone writes a negative recommendation letter (logically broken expression), the letter says more about the writer, than its subject.