Right now SF is not even capable to host 450 homeless arriving every year. What would you do if that number of people arrived every day or every hour?
I don't think immigration laws would permit that. For one, you couldn't "just move" to the US like that.
Within the EU it could become an interesting problem if some countries did this and others didn't. I suspect that if anyone were to try this there'll be some limitations at first, like you have to have citizenship, or prove legal residency for longer than "since the past few minutes".
Anyway, by definition Basic Income is unconditional. Anyone who applies should get it.
Doesn't have to be. Some versions are, some aren't. Given we are talking about a system that does not exist, not sure why you say it is one thing or the other. Some versions give to minors, some do not. Some only give to citizens in good standing (no felons). Conditions can exist and should exist in my opinion.
This means, there's at least one condition: only humans can apply.