Steps to repro:

1. Open Unity;
2. Open attached project and 'repro' scene;
3. Notice that there are two gameobjects (InstancedMulti and Instanced Simple), both having script that is drawing instanced meshes (simple mesh and mesh with submeshes). Both meshes DO NOT use instanced shader on their materials;
4. Launch the scene;

Expected result:
Warning message should be shown, stating that objects do not use instanced shaders.

Actual result:
No warning message is shown.

Notes:
- Some users were already mislead by the lack of this warning message - they thought that DrawMeshInstanced API is not working at all (see case 845514);
- Reproducible in Unity 5.6.0a3 and 5.5.0f1;
- Reproducible on OSX 10.12.1 and on Windows 10.