Method summary
If you can make the eggs invisible while the dragon is taking a nap, she'll probably panic when she wakes up and believes that the eggs are gone. If the scent of humans lingers, she will likely assume those humans recently stole the eggs and have since fled. She won't have time to reason in what ways it might be a trap. She'll have to pursue the humans, or risk losing the eggs. When the dragon leaves the nest to pursue, move in and steal the eggs.
Methods for hiding the eggs
* Magic is usually the simplest solution if available. If an invisibility spell is too high level for the thieves, they might try an illusion or hypnosis spell, which just happen to be particularly effective when the subject is asleep.
* Camouflage or non-magical optical illusions are a possibility, but tend to require intimate knowledge of the terrain the eggs are in. Additionally, this method quickly falls apart if the dragon makes a quick sweep of the area to make sure that the eggs are, indeed, gone.
* Hide the eggs in a hole and cover it up. How would you dig a hole right next to a dragon, you ask? No idea. Ask a dwarf. There might be magic spells available that have the desired effect.
* If there's only a single egg, disguise it as something else. For example, create a sign '<PERSON> was here <3', and place it over the egg. 227
(bonus points if the sign encases the eggs, for the event the sign is moved). This method only works if there's one or two eggs, as placing more signs will be suspicious. The advantage of this method is that it taunts the dragon, increasing the likelihood that it will choose to pursue.
Disclaimers
* This method fails if there are multiple eggs and you only disguise a few. The dragon will have to balance guarding the remaining eggs with pursuing the thieves. Never underestimate a dragon that applies reason.
* The thieves will have to move fast. The dragon is not likely to pursue fake thieves (without so much as a real egg) for very long. The thieves can buy some time by creating a more elaborate trail ahead of time. If they are particularly cruel, they may have the trail lead to enemies of their own or even enemies of the dragon, if she is known to have them.
* If the thieves don't mask their own human scent sufficiently, the dragon may notice. If she does... Let's just say that immolation is not the most pleasant way to die.
* If the dragon notices the eggs are still there, it is likely that the dragon will find the thieves, even if their scent is masked properly. This will likely lead to death in an even more agonizing manner, as the dragon will not have to worry about damaging the eggs while punishing the thieves for their scheming.
* If you value your life, don't steal eggs from a dragon. 164