One particular issue which, to the best of my knowledge, has not yet been raised in discussions on this issue is whether, in the case of the second scenario, the bank letter issued by BKKB will include an explicit statement that the account will then be frozen for 4 months. If so, this would, of course, mean that the funds on the frozen account would then not be freely available during the 4-month period in question, in violation of a specific IMM requirement - with the result that a consequential application for an annual retirement or marriage extension would then almost certainly be rejected.
And, even if the BKKB letter didn't include any explicit statement to this effect, the word is surely likely to spread like wildfire of the bank's change of policy on the Immigration Bureau grapevine - with the result that ALL account confirmation letters issued by BKKB might then, at best, be viewed with suspicion by immigration officers.