A scammer is a person who scams other players out of their posessions and are more common in crowded worlds. Often the scammer will get banned or muted by Jagex for repeated breaches of Honour, specifically the 'Scamming' subsection, as well as being hated by most of the RuneScape community.
Before Trade Limits, PKing Removal and Gravestones Edit
A scammer commits scams such as the Trust Game and many different item scams. Before RuneScape unleashed the trade improvements, people were often scammed of their money.
Several of these scams involved swapping items for similar but much less valuable items, such as the 1004 Coin Scam or the Rune to Iron Scam, where the scammer always got an item or amount of coins with much greater value than the legitimate player. A famous example is Armour Trimming. These scams became obsolete with the Trade Limits update, but have resurfaced with the return of Free Trade on 1 February 2011.
Also, many high leveled scammers lured lower level players with expensive items into the Wilderness in scams such as the YouTube Video Scam, where the lower leveled player usually lost expensive items without knowing they could lose them. These temporarily became obsolete with the removal of PKing in the Wilderness, but have resurfaced with the return of PKing on 1 February 2011.
Other examples of luring went on even earlier, before the Gravestones update obsoleted them. Scams like this included luring a high leveled monster over to a lower leveled player. The monster would usually kill the player while the scammer fled and returned not long later to pick up the victim's items. However, gravestones now protect players' items so only they can pick them up after death. As of 1 February 2011, Jagex changed gravestones so that this effect only lasts as long as the gravestone is still standing. That is, after the gravestone collapses, dropped items become immediately visible to other players, although to make up for this, they increased the timers and removed the prayer drain for repairing and blessing. In addition, gravestones no longer appear in the Wilderness.
New Scams Edit
Even after the introduction of these updates, scamming still continues. Scammers can still steal players' passwords, buy and sell accounts and do certain trading scams. Scams that previously worked by swapping items now leave a red exclamation mark to warn players can still be done, although with a lower success rate. This is done by 'accidentally' clicking Decline when offering the item and, when trading the second time, offering the less valuable item. However, this is often ineffective due to an update that makes the text for a declined trade appear in red.