The chests you are able to thieve from in RuneScape are not safe
Unlike doors, the chests you are able to thieve from in RuneScape are not safe. If you do not take care when thieving from chest, the traps hidden in them will hurt you. To find a trap on a chest, right click on it and select “Search for traps.” Your character will automatically find the trap and disarm it if your Thieving level is high enough. Please note that when you loot the Paladin and Blood rune chests, you will be teleported outside their containing buildings. For the most part, chests do not give very good experience. The only chest that is really worth thieving is the Blood rune chest since it produces a fair amount of profit on top of the experience given. (NOTE: When thieving the Dorgesh-Kaan chests, you will need a Lockpick).
In the past, you could only thieve stalls in the city of Ardougne, but now there are many stall-thieving activities around the globe. Stealing from stalls is a lot like chest looting; however, there are no traps on the stall. Instead, certain in-game characters will be on the lookout for thieves like you and will fight you or knock you out if they catch you.
To thieve from a stall, right click and select “Steal from.” If nobody catches you in the act, you will take the items from the stall and they will appear in your inventory.
You may be caught by the stall owner or any guard type NPC surrounding the stall. To avoid this, try to stay out of their lines of sight.
When training the skill of Thieving, the stalls that require a high Thieving level to steal from are not very useful because of their slow rates of respawn. I would recommend thieving from the Vegetable, Baker’s, Tea, Silk, Seed, and Fur stalls for the best experience.
Please note that the time listed is when stealing from a stall on a crowded world. An emptier world will have a slower respawn time.