I've been to Australia a few times and was also surprised at this sort of thing. The words "don't need to have suspicion of anything specific" is code for "we h

I've been to Australia a few times and was also surprised at this sort of thing. The words "don't need to have suspicion of anything specific" is code for "we have reason to suspect you're hiding something, we just aren't sure what it is". Not appearing to be cooperative further raises suspicions and will lead to more invasive searches/questions. If your goal is to get out of the situation ASAP and be subject to as few searches as possible, be friendly and cooperative. This doesn't mean I agree with how things are. It's clearly a blatant violation of basic rights, but you can't fight it at the border when you're being searched. Raising awareness and making it a political issue is the only way it can change.