People's positions on this issue are VERY interesting.
How is the use of such a "tree calculator" (Yes, in this case, let's call it exactly that, because players with more games under their belt will memorize all "non-standard" trees and know where to take what and where not to) different from using a guard calculator? A damage calculator? PhysMig? For heaven's sake, even template schemes? All of the above allow a person with fewer played matches to reduce the time spent acquiring some encyclopedic knowledge.
The most "dangerous" of the above (including the tree calculator) is PhysMig. People can learn many things from it right during the game, and knowing EVERYTHING listed in PhysMig without exception would require playing millions of matches for every single rare case (which you'd likely never test before a game). And each such detail is a won game. An example? The fact that wyvern poison isn't blocked by anything, but the power of the Father of Dragons blocks it. Such a situation occurs once in a hundred thousand games, but at that critical moment, something peeked at in PhysMig will decide the outcome.
It is exactly the same with the tree calculator. A person who has played hundreds (or even thousands) of games with their favorite Castle or favorite hero develops an eye for certain skill trees and knows that here, between "ballistics and keenness," they need to take keenness, even if the choice isn't the most logical. Where, one asks, is a beginner supposed to get such information if not from an "encyclopedia" of skill trees?
The rest are harmless examples. A damage calculator simply requires knowledge of formulas and saves time; a guard calculator requires knowledge of slightly more formulas. I brought up the example of template schemes in hopes of shutting up those who use arguments like "There are things I don't want to know about this game. You have to find out for yourself." Want to find out for yourself? Then why the hell are you digging through template schemes?
Since cheaters exist, the following steps must be taken:
1. Accept it. Such a thing is impossible to prove. Even someone caught red-handed can (and would be right) say that they've already played a couple of times as Craig with this skill tree / played offline before and know this skill tree almost by heart, hence the "strange" choice. Blindly accusing such a person of cheating will look biased and foolish.
2. "What should be done then?"
Give honest players a program that has ONLY the function of viewing trees and nothing else. Or (even better) - a text file with the trees so they can search using ctrl-f. This is not such a large part of the game as to cause a panic over it.