I don't like RS or Maple.. I always prefered Tibia. I like the graphics more, it reminds me of early Final Fantasy, and there are way more abilities and stuff. I remember falling down a hole (it was night time and I was too newb to have a torch), no rope to get out, and I was slain by poison spiders.. a lot of poison spiders >.<
Anyways, Tibia owns RuneScape, so I switched when that came out. I did play RS though, as an archer.. level 40 something arching, I think it's close to 50. I crafted a lot too, and had an uber-leet outfit. Black clothing, black boots, black gloves, black cape, and full black mithril armor in case I was gonna get owned by someone else
Oh yea, and a black mithril axe, a mithril dagger, and an emerald amulet to help my defense. Plus my godly crossbow of vengeance.
I don't know how you expect to "dupe" RS, the closest thing you can do to advance without work is "scamming", which I used to be extremely good at (Scamming is the RuneScape term for tricking someone into doing something which benefits you but screws them over). Good examples:
Stand by the place where all the new players show up, and try to get one alone somewhere. Say if they follow you, you'll help them. Then, when no one else is within earshot, tell them that if they drop an item (whatever item it is you want), then wait for a minute (it will take a little while to show up for you.. like 2 minutes), and then press Alt + F4, it will become a super item. Alt + F4, obviously, closes the RuneScape window, allowing you to go pick up their stuff before they get back on. It helps if you keep a good distance from them, telling them you will stay far away so they know you aren't trying to steal from them.
Some common ones to just get stuff directly from people is telling them you will imbue their items with something awesome for 1 gold (they think you will actually give them their item back for a single gold). One good example is "Free Gold Plating for all weapons and armor!" or something similar.
Other methods include selling things to newbs at extremely high prices that they don't know any better (like Runes.. making them think that some ultra-common Rune is worth tons of gold), or (you probably can't do this anymore, I'm assuming they changed the graphics by now) you can sell an item and tell them it's something that looks similar. Some people don't pay attention. Or you can put the real one up, accidentally cancel, say it was an accident, and then restart the trade with the fake item, so they don't check a second time.
Some other methods are getting people to follow you to a place that is filled with monsters that could kill them easily, and making sure they get attacked. I remember a pit of giants, a few scorpion places, and tons of monster filled areas this worked at.
If worse comes to worse, you can put all your stuff in the bank, and then go to the place where you can mine blurite (some name like that, it's blue and for a special quest). Just need a picaxe and I'm not sure what mining level. I believe the same one that it takes to mine iron (or maybe no level at all, that's very possible). You run in, mine 3 things of it, and just die. You keep 3 blurites on death. Another place is where those stupid roots come from giants. You can usually run in and grab a few before you die. I've done the latter with a completely new character, and possibly the first one (which is why I think your mining level doesn't matter).
Anyways, that's pretty much all the ways I ever cheated RS. Well.. except the Chaos Tower method. But they stopped that because of me. I hated them after that and stopped playing and started Tibia. There was this place out in the middle of nowhere called Chaos Tower, at the very far corner of the map. There were tons and tons of high leveled monks inside, and they had the power to curse their opponents, leaving them almost helpless to their wrath. Well, it was a very small room all these monks were packed into, the tower was unbelievably small, just this one room. And there was a door going into it, lots of monks inside, and a pitcher of wine on a table at the far wall away from the door. Well, I'd get people to follow me to come get the 'secret wine that can instantly raise your level'. It didn't really, but they never found that out. You see, when you tried to take the wine, a monk would stop you, and then they'd gang rape you. Of course you could flee and run out the door.. unless someone had closed it. It was impossible to flee, open the door, and escape before they attacked you again. By the time you could flee again, the person had plenty of time to close the door, meaning you couldn't get out still. After they die, two minutes later their stuff shows up and you grab it, and since the town the respawn at is about a 20 minute walk, being the entire other side of the map, they can't get back in time. It was absolutely fool-proof. Never failed once. Until they removed the door