@Daniel *********
I understand what you mean with checkpoints, but if they wanted to do that it was much easier to do that the same way as non-o visa.
Checks at country entry are not practical and only a small percentage will be checked.
But I don't want to discuss this any further, the original question was why immigration made people feel unwelcome while they complied with the rules.
I tried to answer that question, and gave the most common sense answer and now it looks like I have to defend that I have the same ideas as the majority in the world.
When people use someting a visain a way it was not intended, they can expect immigration does not like that, but as long as they comply with all visa rules at the moment of entry it is unlikely they will stop you.
When they don't want so, they should close the loopholes.