I was a realtor for several years back in the 80's. I have seen sales fall apart at the closing meeting. It ain't over until the fat lady sings.
The buyers' adult children got involved and talked them out of this community. They, by VA law, have a void contingency in HOA communities. They can read the HOA document and then change their minds.
It would seem easy enough to put a statement in the purchase agreement that states the buyers have read the HOA agreement and agree to it's provisions which should void any back out options.