I believe this is a strictly academic question. Correct me if I'm wrong. Many of the restrictions enacted by the Rabbis (as opposed to those extrapolated from the Torah) were done so in order to ...
The decree of keeping two days of Yom Tov outside of Israel is because Rosh Chodesh used to be determined by Beis Din and its messengers couldn't reach all of exiles in time, thereby requiring people ...
Obviously they wouldn't need a "blech" like we think of one, but would they need some sort of physical alteration to remind one not to adjust the knobs/switches on Shabbos? More specifically, to ...