VBSS training consists of some initial schoolhouse training which is actually pretty good. It's run by mostly ex-NSW types, graded and timed shoot and move, some MOUT-town killhouse training, water survival training in the aviation water survival pool, and you usually end with a few runs on the same underway training assets NSW uses (ie configured like a real merchant, not USS GREYHULL)
Then it goes back to the Fleet to keep these guys current, and of course, it gets fucked up.
Unless things had a major turnaround in the past few years, as far as the Fleet is concerned, as long as they still run a Good PFA, swim 2nd class qual, and meet the same shooting standards as a Fleet FP watchstander, they're individually good to go.
Unit training, they're lucky to get maybe 3 actual practice boardings a month. Usually on your own ship. Maybe a couple more during COMPTUEX or other major exercises, but you usually "take credit" for those.
But it's because of expectations and complacency. All these guys do is hop on dhows, pretty much always compliant, pass out water, hats, gloves, and other geedunk, and look around. Beat cops, not SWAT.