The alcohol issue is a tough one.. The regulations give the crew the absolute and final discretionary 'call' to stop serving someone *if* they reasonably believe that the person is under the influence *or* will pose a risk to safety or security..
The thing that makes this issue difficult on the aircraft is that unlike a typical case of a potential drunken person on the ground, the crew doesn't have the capability to measure objectively nor is their any empirical testing options available.. So, there is a fair bit of discretion and subjectivity in the matter.
To this end, none of us where there to see exactly who did what, what the crew saw or did not see, how the OP acted or didn't act.. and we have only the OP's accounting of the situation.. This is *not* to say the OP is not being honest or has given only a partial accounting-- only that we are in fact hearing only one side of the accounting.
Is it possible the crew was wrong or over-reacted? Absolutely. It is a possibility.. Conversely, it is possible the OP was in fact drunk *or* demonstrated behaviors the crew deemed unsafe? Again, yes it is possible.. and for good measure it could have been a combination of both..
That said, given the fact that the regulators give the final and absolute discretionary call over the serving of alcohol to the on-duty crew, they had the right to stop serving.. but, regardless if they were cut off or not, I do think it needs to be handled in a professional and courteous manner.. so, if that didn't happen, then I do think the OP has a valid issue there..
The bathroom issue is a little different.. I'd ask if the bathroom was not cleaned *prior* to departure then absolutely, it needs to be address by Oman Air.. On the other hand, if the bathroom was "soiled" by passenger use after departure, well then I can't entirely fault Oman for that.. We're not getting specfics of what this "filthy" actually was-- but commonly it's a combination of bodily fluids and solid waste and gray-water spillage.
There are some ways for the crew to mitigate these problem, but since lavatory issues generally involve materials that can carry bacteria and other potentially dangerous infectious pathogens, many airlines restrict what they mandate their crews to do.. So, depending on the severity, it just may be that the right thing to do was to "lock it out" until arrival.
Edited: 18 March 2011, 9:54