How do mainland Chinese and non-mainland Chinese people refer to China?, ...about the use of the term 中國大陸/中国大陆...
Let me first relate an interesting experience.
Many decades ago I was visiting the US via Hawaii. At the Hawaiian airport Immigration counter the officer asked where I was headed, (meaning my ultimate port of call), I answered "the United States" Whoa!, she gave a semi-angry stare and said, "This is the United States"
Being blessedly born with a nimble mind, I casually answered, "I meant the mainland" This seemed to avoid an unpleasant march to the "briefing room" She stamped my passport and I was on my way to the United States.
Now if this had happened in say, British Hong Kong before "unification", and I said I was on my way to "中國", I don't think the Hong Kong immigration officer would have bated an eyelid. But what if it happens now after unification when, politically, (using this term loosely), Hong Kong is part of 中國 just as Hawaii is part of the United States?
I tell this incident to highlight the fact that such questions and answers could potentially cause misunderstandings.
Having said that, and as for myself, being a member of the Worldwide Chinese diaspora, I couldn't refer to China as 大陸, which simply means "mainland", just as Continental United States is the Mainland for Hawaii, simply because I am not a citizen of the People's Republic of China living on any number of Chinese territorial islands, like Hong Kong for which mainland China is 大陸, "the Mainland"
So, for people like me, of Chinese descend whose ancestors left China for Nanyang, (the Southern Seas), generations ago, would simply refer to China as 中国, just like someone from any other country would.
Of course anyone, including non-Chinese citizens, could refer to the People's Republic of China as 中國大陸/中国大陆 and no one would bate an eyelid, perhaps not even Chinese immigration officers; but I could be wrong of course, depending on the level of "political" understanding of such officers.