Electronic Circuits and Projects Forum

How am I supposed to know the environment the user is operating his resistor and LED in.???

You don't, you just mention it, all it takes is a simple note on the calculator that wattage is dependent on 25C free air and you don't have to worry about it! Perhaps you could cross reference with links to the resistor selection calculator that mentions de-rating of resistor wattage. There is no such thing as providing too much information.

Any 1st year student knows that an enclosed resistor will over heat.

The user base here contains MANY people other than 1st year students, including many user which know so little about electronics that it's scary that they're trying anything with it at all, a little prudence about the viewing audience is in order! It's a trivial thing to add this mention I'm surprised you're being so vehemently opposed to needing to mention it.

You will find in engineering that you design to meet the required specification, not the worst case conditions for every component.

Of course you don't, but you also don't provide information without specifying under what assumed conditions the components values are valid. Common sense in electronics is NOT common it is learned from a wide variety of knowledge that has to be collected over time, this calculator is mostly useful to newer users as anyone that has even a modestly basic understanding of electronics can work this out with a basic calculator in a few seconds, new users will not understand any of the assumptions being made.