As I am sure you know, Benes wrote to Moscicki on 22nd September offering boundary corrections in return for Polish friendly neutrality. Moscicki replied on 27th September with the usual positive platitudes - essentially inviting the Czechoslovak side to make a practical proposal. This came on 30.9.38 (the day after Munich) from Foreign Minister Kroft offering Cieszyn to the Poles and emphasising that the offer was being made of the Czechoslovak governments own volition. So yes, the actual offer of Cieszyn/Tesin to Poland was made from the Czechoslovak's government initiative and that is a documented fact.It also makes a nonsense of any suggestion that it was done at the Czechoslovaks' "own initiative".
The timetable for the actual handover of Cieszyn/Tesin by the Czechoslovak government was 31st October to 1st December 1938. It was clear that by then the area, or at least its most strategically significant significant parts, would be firmly in the hands of the Germans who, it was felt, would either not be removable or who would trade the area for concessions in Danzig and/or The Corridor. There was also a feeling that perhaps the next time the "Munich four" met they would use this pretext to allow Hitler to cut Poland off from the sea altogether. For this reason a meeting of Poland's senior government officials, including the President, was held immediately after the Munich conference, which concluded that Poland could and would not now or in the future submit passively to external diktats. This meeting decided to send the ultimatum to Czechoslovakia (although as much aimed at the 'big four' as it was against the Czechoslovak government) demanding immediate handover of the Cieszyn region.indecent haste to pick over the carcass left by Germany does little to enhance its national dignity
Clearly, there was no haste, indecent or otherwise, until such haste was made necessary by the Munich Agreement which was in no way of Poland's making. Unfortunately if a bus starts to leave before its scheduled time you have the option of running after it in 'indecent haste' and risking 'national dignity' or missing it altogether.
There was no 'German' bandwagon. There was only one bandwagon in town and that was a German-French-British-Italian bandwagon. None of the interested parties except the Germans were invited or had any chance of 'jumping' onto it. The Polish ultimatum had a number of objectives both practical (to prevent the Germans occupying territories that Poland had already been promised by Czechoslovakia and the putting aside what was already a done deal as far as the Poles were concerned (there is a reason why gazumping is generally frowned upon)) and symbolic.If that isn't jumping on the German bandwagon, I don't know what is!
The symbolic aspect was a shot across the bows that Poland rejected the right of major powers to interfere in and overturn agreements made by sovereign states without their participation or consent. The 'nothing about us without us' principle. And this is perhaps the only relevant aspect of the Cieszyn/Tesin discussion to this thread regarding The Corridor. There was a clear fear of the Polish 'senior management' (justified in my opinion) that the Munich Agreement could be used as a blueprint for pushing Poland away from the sea.
So far from joining the bandwagon, the Polish ultimatum was an attempt to put a very small spoke (the only one they had) in one or two of its wheels.
While no one involved came out of this wretched business untarnished, an examination of reliable evidence suggests Poland was probably among the least responsible for it's outcome yet seems to carry a disproportional amount of the blame. I am yet to hear a sensible suggestion from the critics how Poland should have acted differently in the given situation, a situation not of Poland's making. The chief architect was Germany, ably (though not necessarily enthusiastically) supported by Britain, France and Italy.
With twenty/twenty hindsight it is probably clear that both Poland and Czechoslovakia instead of looking towards France and other outside powers for support, should have looked to each other in the first instance. In this failing they are in my view both equally to blame. However it is easy to be wise after the fact......