I'm an admin for a small Trello board used to organize action items for a development project, and we've been using member assignment to 'track' all relevant parties to the card's topic. I.E. if Bob is working on a bugfix for code that Jim wrote, both Bob and Jim are added as members to the card.
The trouble with this scenario is that adding a member to a card will automatically set the "Subscribed" flag, meaning that Jim will receive notification e-mails for the card. This is normally fine, but our project manager in particular is wanting to only receive e-mails regarding specific action items she needs to do, not every single card she's involved in (e.g. a "Meet with PM" task that Bob sets up).
Is there some way to add a member to a card without subscribing them? While subscription and assignment are two separate things, they are set at once and I can't remove subscriptions admin-side. Since it's a bit unreasonable to ask folks to log in and manually unsubscribe themselves from the things they don't want to see, the closest solution is for the PM to change her notification setting to "Never," which of course means that no e-mails will go through at all. That's troublesome for a whole other reason, namely that we're trying to show her that Trello is the way to go and without the task e-mails she'll likely forget to check it. 😉
Apologies for the wordiness. I can't find a setting or a good answer via Google so I figured I'd explain the "why?" behind the situation before the questions are raised. This may be a "Don't do that" in regards to how we're assigning members, but I figured it's worth an ask regardless.
Best Answer
The "why" is that Trello didn't used to have a separate "subscribed" and "assigned" concept. Notifications were generated for cards you were assigned to, and there was no way to "unsubscribe" from a card except to unassign yourself (and no way to "subscribe" to a card except by assigning yourself).
This was limiting, so we added a separate notion of subscribing and, because it's usually what you want, set it up to automatically subscribe you when you're assigned to a card (as a nice touch, this was consistent with how it worked before, so people who were used to the old behavior didn't have to change their workflow).
Unfortunately there's no way to change this. The solution to the notification woes is, sadly, "don't do that." If someone doesn't need to be updated about everything that happens on a card, using @mentions to send them notifications when they do actually need to chime in is a better idea.