Pete, your comments are spot on. I too had a disaster around your #6. A speaker brought a presention on a flash drive - in a brand new version of PowerPoint that had just begun selling in stores. The conference center had the older version loaded on their laptop. After the title slide, little comment bubbles kept popping up (not meant for audience consumption). The speaker was furious and he apparently didn't know how to tap dance.
Not even the a/v guy (as per Nadir's comments above - I agree, pay to hire a/v experts) could figure it out, as it was the first time to happen to him, too. Next day, the conference center went out a bought the newest version of MS PowerPoint.
And now I use my own laptop and carry my own VGA cable too. Once I ran into a small hotel that didn't have one. Ack!