And then the partition that has accepted the transfer of gas from a partition that it did not validate now will have all its derivative transactions (and scripts) subject to reversal if later someone shows evidence that the balance was a lie.
You are writing nonsense (and you should know it which is why I am not being entirely polite ... please don't feed the damn trolls because you are not careful to think before typing).
Read what I wrote again more carefully

Read what I wrote again more carefully. And make a rebuttal if you have one. Adding noise to the thread by writing this "read again" doesn't help at all. I read it already. I already explained why it doesn't make any sense. Where is your nonsense rebuttal?
Edit: for the source and destination partitions to merge (even for the history and not the future), means they need to validate each other's history. That is my point that then separate validation is lost. Thus the entire scaling advantage of partitioning is lost. Read again what I wrote! How can you not remember something I wrote just a few posts above:
I already explained that cross-partition spending is possible (i.e. won't destroy the Nash equilibrium) only if validation of all partitions is done by all validators, which thus defeats the scaling advantages of making partitions (shards).