urine sample
Can a police/customs officer request me to give them a urine sample (or anything that would confirm or disprove) their suspicion of me taking drugs (or other dangerous substances) even WITHOUT my consent?
Are the laws similar across different states?
Which legislation(s) should I refer to?
Re: urine sample
The authorities don't need your consent just to request a sample. Making such a request is how they seek your consent, so requiring them to already have it would not make sense.
Your question presumes that the rules which apply to police also apply to customs officers, but customs officers have considerably more leeway in most matters. Either way, though, there is no rule against asking you to provide a sample.