Should I avoid proofreading like a plaque?

 I awoke a bit late this morning and read Robert's latest post. 

He was giving advice on how to live, but his last statement puzzled me.

"Have fun and avoid sin like the plaque."

Because he used the word 'the' before his last noun, I assume that he wasn't talking about this.

You'd tend to say, "Avoid plaque."

He was more likely talking about one of these.

Though, to be honest, I don't
know what this one is on about.

I looked up a few more plaques to see why they should be avoided.

I couldn't see much harm in this one.

Plaques are often put up to commemorate people or things. They generally don't cause much harm, if any. I mean, murdering someone or robbing a bank would possibly do more harm.

To be sure, I thought that I'd better look up the definition of sin.

"An immoral act considered to be a transgression against divine law."
I assume that 'divine law' has something to do with gods. Maybe there is a plaque that says this? Yes, that would make more sense, though he really should have said,
"Have fun and avoid sin like the plaque says."
To be fair, though, he should have showed us a picture of the plaque.


Maybe proofreading needs a plaque?