Forza Motorsport 7 Message Board  

After some experimentation, I've come up with a hypothesis for how to avoid bans.

If you open the game with Internet connection without activating the Trainer and disconnect from the Internet, then you ought be able to play the game and use the Trainer avoiding a ban.

I found that you require connection to the Internet in order to start the game. Afterwards, disconnecting from the Internet does not kick you from the game which is a nifty little thing we can exploit in order to use the Trainer as we wish. Buying cars from the Autoshow does not seem to trigger any type of mechanism that bans you. Be extremely careful when interacting with the Online components such as the Auction. The game economy is, beyond a reasonable doubt, what the administrators of Forza care most about preserving.

Procedure:
1. Open the game, requires connection to the Internet.
2. At the main menu, disconnect from the Internet. The game will not boot you from your session.
3. Activate the Trainer.
4. Enter the game and cheat in a reasonable manner, do not go crazy with the cheating because you might find yourself banned when you go back online.
5. When you wish to go back Online, EXIT the game AND the Trainer.
6. Restore Internet connection, open the game and enjoy it.
7. Repeat step 2 as you see fit.

More data would help to prove my hypothesis, across both (trainable) Forza games on Win10.

Just letting everyone know I have been banned from Forza Motorsport 7 using my main Xbox Live account until 5/10/2047, I was expecting it anyway, I just thought I will be lucky this time.
The reason why I am now banned is for using the trainer to add 900,000,000 credits to my account.
So for anyone that still does not believe that you can and will be banned for adding a ridiculous amount of credits be very careful on how much credits you add.