Much of the superstition of Macbeth the Scottish Play originates from witchcraft which is featured prominently in Macbeth the Scottish Play. The invocation of the Powers of Evil has supposably conjured devils at the first performance of Doctor Faustus in 1592 (or there abouts).
Some rationale for the Scottish Curse has been the dim lighting which makes it much easier to make a mistake or trip over something. Furthermore, there are 8 scenes that involve combat (with axes, daggers, swords, etc...). Adding in the fog or smoke (which makes the stage slippery and things hard to see) and trap doors and other
theater special effects, there are many opportunities for the accident prone novice, and more than enough for even a seasoned veteran to spawn a disaster. And just for fun, toss in the fact that it is the shortest of Shakespeare's plays and thus the least likely to be completely rehearsed (something added at the last minute to the repertoire,
after all, everyone knows Macbeth the Scottish Play).