2A.M-R Answers

In 21^st century the main obstacle is invisibilisation. Additionally, money is stolen by teleportation. However, it is achievable mainly because of invisibilisation, and thefts by teleport would happen much more rarely if there was no invisibilisation. (Scanner IVSigma, Cont.)

Additional obstacles are malfunctions of generators, mainly wind and fire, because wind is difficult to be evoked due to poisoned environment, and fire is invisibilised in its work. Wind is actually also invisibilised, so fire is the best alchemical generator in 21^st century. However, invisibilisation blocks users from taking full advantage of any fire. (Scanner Kyoto, Cont.)

Invisibilisation in 21^st century is made of two components: clearance paint, which is a liquid applied onto all objects of earth, and 3D films, which are independent movie figures applied onto all objects of earth. Clearance paint does cause the basic invisibilisation, while 3D films additionally cover all that is left. 3D films are used to camouflage things into different appearance, and thus for example golden coins may often be visible and tangible (3D films are tangible) as green cucumbers. (Encyclopedia Eon, 2En.3Ep.3Er.)

Other obstacles than invisibilisation through clearance paint and 3D holograms of both generators and their products do not exist in 21^st century, except for theft by physical attack or teleporter. It is important to know that money is the number one object category subjected to invisibilisation, and the number one object category desired by thieves. (Scanner IVSigma)

source: crystal ball