On the French avast forum I am monitoring, none of the people who accepted a first trial received an e-mail.
For good reason, this trial is not an order until it expires and the automatic renewal does not start until after the first payment.
However, it may be different in other countries.
Edit:of course as far i'am concerned (already a paying customer with account),if I want a trial for another avast product , I could ban it in my avast account.
Edit2:
P.S. I already stopped the auto-renewal of my subscription, but cannot understand whether it was enough.
Sorry, I didn't see that.