Precisely, only for the mods i suppose, who if they died, the adminstrators and fellow mods will also know.
As for ordinary members, let's say someone had passed on, no body would know actually. People may eventually think that so and so had not come into the forums for a long time, so maybe he/she grew out of it, too busy or no longer interested, sold of his/her PC, married, etc.
But perhaps that guy/gal had met with an traffic accident and had passed on, or perhaps the gal/guy had cancer or such, which he/she did not reveal to fellow forumers, but just wanted to have friends to chat with...
When they died, we assumed they left the forum with other reasons.

As we all know sgforums have 10k+ forum members, of which perhaps some have double accounts, so in actuality we have at least 4-5k real life members. And the forums have been around for 6-7 years i believed. Its actually possible that someone may have left us.....

We will never know......cuz their parents/siblings/friends will never usually log on onto the forum to tell it to his friends..