Does this say that if the installer uses encapsulated Rebar in a pool 680.26(B)(1) that the alternative means is a 12" square grid of #8 with a clamp at every intersection?? That will bump up the price of a pool a bit

I think we need to know what code year you are looking at 2002 or 2005 before your question can be answered properly. See there are changes in the 2005.

I have read through all the ROP and ROC submissions related to this section and it does appear to require what you have posted. The wording in the 2002 NEC, section 680.26(B), "provisions shall be made for an alternative means..." didn't provide any assistance on what that alternate means can be. It appears the new 680.26(C)(3)(b) spells it out.

Mike, 2005
Bryan that is what I seem to get out of it. It appears this is a defacto ban on encapsulated rebar in a pool, not that I have ever seen any.
Nobody is going to sister the rebar with 8ga copper. joined at every intersection. They don't even tie the rebar at every intersection.

BTW if this IS what is says will we start requiring the #8 copper grid in fibermesh decks within 3' of the water?

Not exactly. The use of the alternative means (field-fabricated bonding grid) to establish the equipotential bonding grid to extend under the deck constructed by paved walking surfaces as established in 680.26(c)(3), is only required when the deck is not constructed with poured concrete, wire mesh, and unencapsulated reinforcing steel.

Mike, I haven't seen any steel in a residential slab in years (other than MY house). They just use fiber mesh concrete. That includes pool decks.

The more I read 680.26(C) the more it sounds like this #8 copper grid even has to go out under a brick paver deck. That will certainly be a surprise to pool installers.
If it is concrete they can just put a 3' band of 6x6 wire under it, bonded with a #8 to the pool shell steel but brick pavers are still "paving" and they get laid on compacted sand. Will they need the copper grid in that sand? 680.26(C)(3)(c)

Yes that is correct, if you use concrete with the wire mesh that can be connected to the pool shell steel you’re good to go.

The alternate method is used when the paved walking surface doesn't have anything in it to bond to form the equipotential plane, like fibercreet or brick pavers.

Also just as a side point, in the 2002 code a copper #8 solid conductor was permitted to be used for the bonding grid per 680.26(c)(3) as the alternate means per 680.26(b)(1) when the rebar is encapsulated.

That has been removed and it is no longer permitted in the 2005 code to be used as the bonding grid.