My source would be the appropriate federal statutes. Since most of the facilities that accept incoming adult mental health cases are government run (most usually a county hospital) they become subject to not only the patient dumping statutes, but the statutes under 28 U.S.C. 1983, 18 U.S.C. 241, and 18 U.S.C. 242. The 1983 statute provides a civil cause of action against a government-affiliated employee, and the later statutes involve criminal offenses involving constitutional civil rights which government-run agencies are always subject to. The eighth amendment prohibits any government-run agency, which includes any government-run hospital, from violating the eighth amendment cruel and unusual punishment prohibition, which historically includes refusal to provide adequate medical care within a reasonable time frame. What constitutes "reasonable" is an issue of law that the court must decide on a case-per-case basis, and is something that a federal district judge must ultimately decide. [Law enforcement are not allowed to determine what constitutes "Reasonable" for these purposes because no statute defines the term "reasonable" as used in the criminal statutes under 18 U.S.C. et seq.) ].
Hence, the question becomes whether or not it is "reasonable" for a facility to wait one to two hours to examine a psych patient whom, is by DSM-IV defintion, deemed "unstable". (The DSM-IV is considered the holy grail of mental health practice, and is considered to be an absolute authority in the U.S.) Since EMT-P's don't get any psych training whatsoever beyond "stop-gap" measures such as temporary chemical restraint (which has criminal law considerations of it's own to consider and is considered highly problematic unless one can articulate absolute need at the exact moment of time.), We are largely in over our heads in being able to prevent suicide.
This is because a lot of patients whom need chemical restraint to avoid suicide aren't "combative" in the sense it applies to the EMS world- in that they aren't combative against you, but are rather combative against themselves. Therefore, most patients that actually need chemical restraint don't fall within our classic protocol on the subject. We couple that with the fact that, because we're not trained specifically to articulate mental health state in the language that is inherent to "psych" treatment, MC will be reluctant at best to authorize chemical restraint until things have gotten to the point to where in reality it should have been done way before then. Hence, it becomes that the receiving facility is best equipped to handle the definitive emergency procedure as applies to this type of case, where it is beyond the bare basics, and beyond what the EMT-P is prepared to objectively recognize beyond that of the average citizen. (in that anyone can request a mental health hold for an individual.) This is why psych nurses get training beyond that of an R.N. as applies to the mental health field specifically.
The thing is that "stable" has two totally different definitions depending whether we're talking the physical or mental sense- however, the court will follow the "mental" sense in cases of a suicidal patient, which is beyond our scope of training. Hence it becomes the receiving facility is refusing to deal with a clear emergency in much the same way as if we were to wait 3 minutes before initiating CPR in a cardiac arrest. Regardless of "bed space" they have the duty to stabilize the patient within reasonable capability. Waiting an hour to do something without referring the patient to a facility that is equipped to handle the situation more expediently is medically inappropriate and incurs legal liability under the "Reasonableness" doctrine, because a "Reasonable person" in the eyes of the law is a person without advanced training, but a person whom has "common sense".
The potential net result is that the paramedic incurs liability for acting beyond scope of training in accessing the real potential for harm (since we have no formal mental health training) , and the receiving facility incurs liability because their actions were unreasonable in the eyes of the law.
