Also doesn't the reasonable suspicion have to be specific to the length of detention or the breadth of the search? Being stopped by police so they can verify your appearance, see if there is any obvious evidence of involvement (such as blood) or ask any nearby witnesses if they saw you committing a crime should require, in my thinking a lower threshold of suspicion than if they are handcuffing, arresting, detaining and bringing you into a police station for a lineup. (Just in the same way that doing a search for drugs in someone's car doesn't mean that the police can also search that person's house).
As for the person holding the knife and being shot. I am of the opinion that the person should be posing a clear threat to police to justify such excessive force. The police should avoid escalating the situation and should take a defensive stance, if at all possible, to see if the situation can be handled with less force.
I don't think the waiter/cop is a good comparison. You might have a better comparison with a personal body guard, but I don't see someone serving you food and someone who puts themselves in harms way for your safety at the same level, even if they are both being paid for it.
For me, trust is better established and progress happens when both parties try to work together and move forward in good faith. I don't think a "I won't respect you until you respect me" attitude will get us anywhere.