Okay, with multiple responses, I will go ahead and give the rest of my story.
I was ROing at a LE match, and we had several accomplished trainers there as well. Anyways, we had two (SWAT) officers have this problem, and they responded just as most as you have said, and as their training dictated - tap, rack, *reassess*, bang. [They were using Glock 22s]
However, for one of the officers, all he got was another click and he attempted the same drill which didn't solve the problem (his mag was empty and was not engaging the slide stop).
The second officer was able to get his gun running again, but only for 1 more round until he was out of ammo. When his slide locked back, he hesitated because his mind was still in the malfunction-clearance mode and it took him an extra second to realize that he needed to change magazines.
After seeing this, one of the instructors talked with them, and when asked how many rounds they thought they had fired before their guns malfunctioned, both of them guessed "10 or so".
The instructor then said when he teaches classes, he (obviously) teaches the tap, rack, bang; but he also teaches that if you get a *click* and you know that you have fired the majority of rounds from your magazine to skip the 'tap, rack, bang', and instead eject the mag, reload a fresh one, and rack the slide. He had two reasons for this:
1. Your magazine is dry and has failed to engage the slide stop - 'tap, rack, bang' will not get you a good round no matter how many times you do it on an empty mag.
2. You have a dud round and 'tap, rack, bang' will get you up and running again, but only for a few rounds at most at which time you will have to reload and be vulnerable again.
After thinking about this, I agree with him that it has merit, but I also see its flaws.
One flaw would be that while some people are very fast at changing magazines, it will most always still be slower than a 'tap, rack, bang'. And if that is all you need to finish the fight and stop the threat, then wasting the extra tenths of a second to reload a fresh mag could be costly.
Anyone here have any thoughts on the matter?