Being in charge of correcting for the מגילה is a very scary task. It's enough that everyone is so uptight about making sure every syllable is pronounced correctly. What makes it worse is all the different שיטות and knowing what might be a mistake and what is not. I once was "right-hand man" (I might have stood on his left) for someone who chose to repeat the פסוק for every word that was a matter of significant dispute, not just להרוג ולאבד and לא עמד בפניהם.
On that note, the רב of our shul told me this past week he once heard someone read בפניהם and not go back. He was very troubled as he read in מנחת שי that לפניהם was in fact the more likely correct word. However, he later found in קסת הסופר by the בעל קיצור שלחן ערוך that בפניהם is in fact correct. Surprisingly, to support this assertion, he asserts that this is the way it is found in the Concordance!
So, anyone who has any advisories to offer, anything to look out for, please post.
For anyone who is not registered as a contributor, I have made a new link on the right to send questions or comments to be posted.
Here's a good one from MG in the comments:
A lesser-known mistake but one that I've heard: "צהלה ושמחה" - the first "ה" in "צהלה" is a חטף-פתח. If pronounced as a קמץ., it changes the meaning to a noun.
Please see more in the comments below: