Could you explain the setup? Who would access the SMB and who’d access Dropbox’ web interface?
If it’s running on a server with a network-shared folder, I don’t see how that’s an issue for Dropbox. If you were passing around Dropbox credentials for a single user, that’s definitely a breach of ToS.
Had a business account, multiple users in charge of their little zones. Worker bees do work, drop it in a dropbox folder as they go. When they're finished, they tell the person in charge of their zone it's ready, and that person ships it off to the client.
Nothing was TOS breaking there, just that it couldn't detect changes to the folders, so, it would never sync. Triggering a manual re-sync would just hang indefinitely and never finish.
It’s right there in the ToS: “Don’t share your account credentials or give others access to your account.”
You might consider “one company” as a single entity, but it’s extremely clear from the nature of the product that Dropbox is meant to share files between accounts, not “one account for all”
If you had multiple accounts as designed, you wouldn’t need SMB.
I’m only saying this because it sounds like you’re blaming a company for not bending their ToS to your liking. I stopped using Dropbox myself a long time ago as well.
If it’s running on a server with a network-shared folder, I don’t see how that’s an issue for Dropbox. If you were passing around Dropbox credentials for a single user, that’s definitely a breach of ToS.