Security is protection against someone intentionally wanting to do you harm.
For a simple and short email without much importance, this can be ok and therefore in such message, you can accept some mistakes, as long as it does not distract too much.
However, for a report on something important, I expect the writer to review the text, by preference on paper (given that some types of issues are less obvious on screen). He should reread it to see if he did not forget things, to check if his line of reasoning is clearly explained, if results are correctly represented, figures are printed as they should, etc,
If he is doing that work, it is only a small additional step to also correct the spelling and grammar errors. I never see reports which are excellent, apart from grammar and spelling. The reports with a lot of grammatical errors always also show other problems.
There is only one exception to the rule above: reports written in English by non-native speakers.
With the addition of a leap second, you run the risk that some alarms will go off, indicating that there is a potential timing issue. This might cause the shutdown of certain systems.
Using NTP is not always an option: older systems cannot always connect to an NTP server (what with a 20 year old radar?), you need additional secured datalines, etc
"An idealist is one who, on noticing that a rose smells better than a cabbage, concludes that it will also make better soup." - H.L. Mencken