What part of "optional" didn't I understand?

I was sending an invitation on LinkedIn and didn't feel like sending the default note. So I deleted it. After all, it's optional.



What part of "optional" didn't I understand?

(If you like things like this, you might enjoy this site.)

Grrr Would people please be precise

This was sent around at work:

נושא: ראו הוזהרתם :)

לתשומת לבכם,

עקב פריצה לרכבו של אחד מהעובדים, אנא המנעו מהשארת חפצים בעלי ערך ברכב החונה בחניון.

ראו הוזהרתם.

Now, I know what they want to say, but I have to stop myself taking what was written literally - which implies that until that car was broken into, all was well. But now the risk is greater.

It would make sense if that car had contained everyone else's car keys...