Thanks for all your responses! You're right, the route checkers really do not do the job I would need, and they may complicate matters a lot. I was testing them a bit too...
However, it is very important to ensure unchangeable split positions. Also, ideally the splits should be put on such places where they ensure correct track sections are used.
Going through the currently supported layouts, I discovered maybe 2 tracks where small changes were needed, like moving the split point to the minioval (F25), moving splits to a bit different spots (A31, I think), and creating a new (2nd) split (A33, if I am not mistaken).
I hope the layout creators can live with these changes. What I'm trying to do is to get maximum safety that all the lap times on custom tracks are correct and mostly "uncheatable" by updating layouts (and path files).
I have all these layout checks done now. The code requires specific, hard-coded positions of split/finish lines and also of restricted zones, if they are justified. And they can be, I use restricted zone on F25 as additional safety measure.
Except for checklines and restricted zones the other objects can be freely added or removed, I believe this is the correct approach... Tomorrow, if time allows, I will upload here the updated layouts for your approval, comments, etc...
Again, thanks for the feedback.
Airio 2.5.6 is almost complete now. When it is released, all current AIRW custom track lap times will be removed and only the ones coming from version 2.5.6 and newer will be accepted.