Quotation marks

Exiting the local pub on Sunday evening, I noted a hand-written sign affixed to the wall next to the door.

It read (and I paraphrase):

Please show some "courtesy" to our neighbours and leave the pub "quietly"

The quotation marks were quite showy, in a 66 - 99 style.

This brings this Abstract directly to the main point - what are the different applications / interpretations for the quotation marks as used by Urban society these days?

My prima facie reading of those quotation marks is that the sign-writer is being sarcastic in the extreme, i.e. 'Show some so-called courtesy to our neighbours and leave quietly - by your own (possibly outrageous) definition of the word quiet', and is written in defiant response to some recent complaints about the noise.

However, it seems more likely that the landlord is actually asking for some courtesy and quietness of departure by the normal everyday definitions of those words. In which case: why the showy quotation marks???

I daren't ask the landlord (just like in the end I didn't dare to ask the 'Unlock Unlocking' shop man - I was honestly going to, but bottled it after waiting too long for him when he was on the telephone), therefore I must appeal to Urban interpreters in the wider world to provide explanations.

I await your comments with relish.