The intent of a warning is both to advise of a future potential danger as well as to offer advice on how best to reduce one's exposure to that danger. While it is reasonable to advise of certain specific dangers, it would be highly unreasonable to warn against every potential danger. Hence, there are some circumstances where warning is merited and other circumstances where it is not. To determine when you should warn and when you should not, simply consider whether the warning is likely to do more good than harm. Warnings are good when they alert people to something latent or not obvious. For example, the fact that aluminum dust can explode under some circumstances is not generally obvious and should be warned against. The fact that a knife is very sharp and requires some degree of caution when being used is generally well understood by adults and is taught to children at a very young age. Warning people that knives are sharp may be more harmful than beneficial. People could become acclimated to warnings. There is a proper balance of when warnings are helpful and when they are a hindrance.