All you can do with this sort of thing is raise the bar by reducing the number of people who can break it, or who are willing to spend the effort to break it. With publicly available source code, the method you describe raises the bar to exclude... people who can't build it from source or make a trivial modification to the source (find the export code, reverse the sense of the test).
Back on topic, I've assembled a summary of what people in this thread have so far said they would want (filtered somewhat through my interpretation of the Right Way to do things):
1. Handles all DM computations (DaveMage)
2. Intelligent random encounter generator (DaveMage)
- Controlled by many optional parameters (DaveMage)
3. Knows contents of every WOTC D&D book (DaveMage)
4. Simple map editor (DaveMage)
5. Random dungeon generator (DaveMage)
6. Random city generator (DaveMage)
7. Random world generator (DaveMage)
8. $59.99 or less (DaveMage)
9. Comply with copyright/licensing restrictions while still being a
useful D&D product (boB S)
10. Catalog of published/online source material (whether directly
supported or not) (Alan Shutko)
- adventures
- plot hooks
- character
- locations
- spells
- treasures
- RPG system
- difficulty
- original campaign setting
- location
- type of location (i.e., frozen arctic, plains, swamp)
11. Stores annotations of catalog entries (Alan Shutko)
- personal notes
- adjustments
- RPG system conversions
- campaign notes
12. Catalog (and annotations) can be shared with other users (Alan
Shutko)
13. Separate DM and player views of data (Alan Shutko)
14. Ubiquitous hyperlinks (Alan Shutko)
- e.g. Wiki-like links in user-entered data
15. Some kind of link between catalog and online information
sources (and stores) (Alan Shutko)
- e.g. Amazon
16. Sanity checks on rules customizations (boB S)
17. Handles (virtually) any RPG system (boB S)
18. Supports online play (LAN or Internet) (Jeysie)
19. Handles all player character sheet calculations (Jeysie)
20. Multiple views of character sheet data (Jeysie)
- including "'cheat sheet' where you can look at all your mods
at a glance"
21. Character data shareable between players (Jeysie)
22. No unnecessary difference in treatment between PCs and NPCs (Jeysie)
23. Handles various necessary dice rolls (Jeysie)
- e.g. skill checks, ability checks, attack rolls, damage
rolls, saving throws
24. Manual dice roller for ad hocery (Jeysie)
25. Dice rolling history (Jeysie)
- time, player, purpose
26. Battle map with shared whiteboard features (Jeysie)
- grid and "pogs"
- ability to draw assorted shapes
- temporary overlay options (what exactly is that?)
- text labelling of things
- different views for different players and dm
27. Combat tracker (Jeysie)
28. Chat with logging (Jeysie)
- optional builtin chat
- support other chat protocols (e.g., IRC bot interface)
29. Low hardware requirements (Jeysie)
30. Low bandwidth requirements (Jeysie)
31. Minimal dependencies on additional software (Jeysie)
32. Should operate on an isolated LAN (or single machine) (Jeysie)
33. Multilingual (Firzair)
34. Modular set of tools (schporto)
35. Undo (fancier than just undoing last action) (schporto)
36. Microsoft Surface tie-in? (schporto)
37. DM can break or modify any rule, any time (schporto)
38. Highly extensible (Firzair)
39. Inventory generator (Firzair)
40. Treasure generator (Firzair)
41. Character generator (Firzair)
- generates NPCs and PCs
- uses inventory generator
42. House generator (Firzair)
- generates residents
- probably want generators for other kinds of buildings
- businesses
- temples
- castles and other fortifications
- palaces
43. City generator (Firzair)
- uses house generator
44. Freeware/open source (Firzair)