So it becomes a matter of where to draw the line? It's tricky isn't it... I must admit the first time i saw the -ve I was unsure but then on second reading understood... Where to begin with what can be abreviated and what should be left in full?

Let me try to fly this baloon:
If an abbreviation can be found in an authorized (manufacturers) datasheet it is legal, if it can not be found there it will be banned unless it is explained in the post. I have yet to see a datasheet where 'u' means 'you' and 'lol' is used.

Erik

PS The above relates to the american expression for suggesting something while being unsure if it will work which is to "fly a trial baloon"