@anon96036341, I finally got the answer to if your method is allowed.
Myself:
Hello, I notice, under Authorized User Services #9, the TOS does not allow multiple free accounts. If someone has multiple free accounts because their intention is to subscribe and merge them at a later date, does this temporarily violate TOS due to having multiple accounts?
Proton:
Hello,
Thank you for contacting us. I apologize for not being able to respond sooner.
Please note that It is not a problem to have two Proton accounts. However, be aware that having multiple free accounts (e.g. username hoarding, creating bulk sign-ups, creating and/or operating a large number of free accounts for a single organization or individual) is against our Terms of Service.
https://proton.me/legal/termsWhile you can have more than one free account — a backup email address — having too many free accounts is not considered an acceptable use of our service.
Also, please note that attempting to create multiple accounts will trigger more difficult verification methods such as Email or SMS.Feel free to get back to us if you need any further assistance.
Kind regards,
Kind regards,
Vladimir M.
Customer Support
Proton Mail
We are allowed a second free account as a “backup email address,” whatever that means.
Therefore there would be no issue with making a second backup account you aren’t using before upgrading it to consolidate with your main account. It’s strange to me they wouldn’t mention backup emails in the TOS, but it appears that your method is fully viable, albeit complicated.
Someone could also use vouchers for multiple years this way I think.