Should I read it or not?

Reading through some of the suggestions for future polls, I came across this rather odd one.

I don't think it will be listed as an actual poll, because it seems to me to be too obscure, but I thought it might be worth discussing to find out where the idea originated...I've never heard of it.


The poll suggestion was:
SHOULD I READ IT OR NOT?
Should the last line of the script be read before opening night or not?
- Never!
- Not on purpose
- Doesn't matter
- Who really cares
- I love to say Macbeth



Seems strange to me that the most obvious option, "uh, YES" is not listed as a voting choice. So I am assuming that this is supposed to be a theatre superstition, that you should not utter the final line before the show opens?
Have to say I've never heard of this, and I've certainly never seen it observed in practice...in fact it seems to me to be a highly undesirable habit.
Can anyone (perhaps the author of the poll suggestion?) shed some light as to where this notion may have originated, and what it's meaning is? Has anyone ever actually been in a production where this was observed?

Cheers
The Poll-tergeist

[%sig%]