since i lost my frequent flyer status in may, i am been flirting with overweight baggage charge by packing to the brim; and testing both my and the ticketing officer's resolve to not charge me. basically, i am bringing remnants of stuff left over in singapore. one could argue that it's not worth risking the overcharge, as every kg over is $60/kg but. still, i get a kick out of seeing if i can get away with this everytime i travel back down under. so far, the score is 4-0 to my favor! my luggages (typically i check in 2 pieces of luggage) weigh anything from 29 to 35kg.
i kind of figure out the following to get the odds in my favor:
a. it helps if you travel with the airlines more than once. it gives you ground to tilt things to your favor.
b. altho' the weight limit is 20kg for economy (provided you do not have a frequent flyer status like pps or krisflyer gold), you can still get away with about 25kg, easy. every kg after that is a risk you take and you need to figure a way out the tangle.
c. it helps to check-in early. typically when the plane is `empty' earlier on, the ticketing officers are more lenient to a lesser extent. if you check-in late, you will not be able to leverage your position especially if that particular officer has checked-in previous passengers with loads of luggage.
d. `choose' your ticketing offer if you can. i once let a passenger behind me thru' because the ticketing officer who's supposed to serve me is rather `strict' looking. i will eye the 1 or 2 options i have where i think the officer is `friendlier'. it worked in that instance altho' i will never know if it was a good call on my part.
e. always smile and don't get defensive. you are basically at their mercy so you will never win if you `exchange words' with the officer. it will also help to casually ask if the plane is full prior. if the plane is half full, you can use this fact to your advantage if needed.
f. always feign ignorance and over-dramatize to look shock when they tell you the weight of your luggage. and then asked if they can waive it. looking distress can help sometimes; pleading works too...
g. if all things fail, asked to see the duty manager. they have the power to over-ride the officer. you need a bit luck though at this stage.
h. a good ruse is to mention that it was your brother/sister/mother-in-law/any close relative that pass you the items to bring over to your brother/sister/wife/any close relative, hence you have little control over the weight of your luggage. sometimes they sympathize with your plight and you get away with it. i did this once when i told the duty manager that it was my my mother-in-law who packed `the other bag' full of foodstuff to her daughter/my wife and that if i can't bring it with me, i will have to discard them in a rubbish bin, rather than to pay the exhorbitant fee. i got away that time too.
i. last but not least, if you were ever once a pps, star alliance (gold) member or any of the frequent flyer privilege card holder, mentioned that you were once their preferred customer. it was the financial crisis that resulted you not traveling so frequently and you ramained a loyal customer to the carrier regardless. sometimes, it can worked as well. unashamedly, i use this trick too once when i was going nowhere; and it worked too.
admittedly, one needs a lot of luck in such instance. but as they say, the more prepared you are, the better your luck will be.
good luck!
disclaimer: i think all of the above will certainly not work if one travels on a budget airline. so, don't even comptemplate it. and of course, i tested the above only on a couple of carriers. i have not tried the others, so don't send me with a lawyer's letter if you got hit with a hefty surcharge if you attempted any of the above.
shankly came back with a `i-am-not-quite-sure-what-it-is' clay sculpture. it's good effort though; even leonardo starts from the bottom. 
