Cool story. I've had people tell me incredible lies about their experience as well.
I would have been very scared of his speargun but two things the OP mentioned seemed strange. One, that you never bring a loaded speargun to the surface (since when is that a problem???? ... for someone who knows what they are doing.
Second he grabbed the divers waist strap, overpowered him and made him do safety stops (plural) for an ascent from 60 feet.. when the guy was incapable of switching second stages and his pressure gage read nearly zero. Making the guy do unnecessary stops when he is "out of air" and on the edge of panic seems like a poor decision to me.
I think I would have done a direct ascent with no stops, especially if it was such a short dive with a guy huffing on a 72 cu-ft bottle. I also think his speargun would have somehow gotten left on the bottom, as well.
These rules or guidelines are ones that I use and kind of a loose standard so to speak of excepted speargun ettiquette (sp) where I dive.
With freediving a loaded speargun on the surface is exceptable because divers need to be loaded up and ready when they decend. But, loaded guns are supposed to be pointed down range and pointed away from other divers with the safety on. The safety can come off as a freediver decends or just prior to a shot.
Freediving is also a more solitary sport and if in teams, both divers know what to do and how to conduct them selves with loaded guns on the surface. If you know what your doing there isn't a problem.
With scuba diving I do not like people around me with loaded guns because it's generally a buddy situation of two or more and people decend all at the same time and ascend all at the same time meaning there are other divers in close proximity. There is no reason to have a loaded speargun on the surface with scuba because 99.9% of fish shot are on the bottom around here, and with scuba there's plenty of time to worry about loading your gun underwater. A loaded gun in the water column or on the surface is just trouble. Once on the bottom guns can be banded up and the hunt begun, but guns still need to be kept down range and away from other divers. Guns do go off once in a while by themselves when pins break or triggers wear out. Or a finger could brush against a trigger setting it off.
Another thing is we have some very low vis so care must be taken to know what's behind your target.
So anyway these are the rules that I and my regular buddies go by. Other people may have their own rules.
This guy obviously didn't spear much otherwise he would have known some ettiquette. Even common sense would say you don't go waving a loaded gun around on the surface not paying attention to what you're doing or where you're pointing it when there's other people around.
The ascent from 60 feet: Well, my first reaction was to grab his waist straps and hold on to him and make an OK signal in his mask, like "I got you don't worry about it".
My main concern was just to keep him from blasting to the top. I know that when we got to the surface his gauge was pegged on zero but it could have had 50 lbs in it who knows. From the time I grabbed him on the bottom to when we got to 15feet he was frozen.
I know I had plenty of air, and to tell you the truth I was so F-ing mad and disgusted at this point I guess I figured if he sucked his tank dry he wouldn't have a choice but to grab my reg would he? Maybe then he'd get a clue and suddenly remember a few basic skills if he really thought his ass was on the line. He still thinks it's funny! In fact maybe that's what should have happened to drive the whole reallity of this thing home in his brain. Maybe he wouldn't still be so mouthy.
So as to why I did a stop? I don't know, I just did. Maybe so I wouldn't get screwed up, I guess it's automatic. To tell you the truth our stop at 15 feet lasted about 1 minute before he started clawing and drug me to the top and I couldn't hold him anymore. He didn't run out of air though, but you bring up a good point, I should have just done a constant controlled ascent.
Or, thinking about it later, maybe I wasn't thinking about how much air he had because I was too busy thinking about how I was going to wrap my fingers around his neck when we got back to shore.
