I think the point is getting lost here.
If you're No1 for take off then then its a no brainer really, but if your sat in a line of 15 a/c waiting to take of 090 at LHR then there is at least 15 to 20 minutes before you are going anywhere.
The point is that all situations are different and should be treated as such and more importantly those on the a/c and not sat in an office should be given the respect and responsibility to act accordingly. As some one posted earlier the pax concerned could have a health problem and why should they divulge their very private information to crew on boarding? If the need arises to to make crew aware of their health concerns then that is the right time to do so.
We are in danger of becoming rather officious if we insist on the same level of compliance to rules regarding a passenger who is actually interfering with the safe operation of a flight and someone who just needs a pee! After all what would those of you who supported the police being involved have done if the pax concerned was a heavily pregnant lady? As you can see all situations need to be addressed individually. Illegal they may be but that is just the letter of the law not the spirit of it.
I have always found that helping my passengers not only makes them happy but it makes day a hell of a lot easier.........
6