I saw a thread some weeks ago where someone was complaining, that he received a message about investment from someone in this forum.
Most of this old members that are messaging newbies in other to scam them has already been given negative feedback by DT members in this forum, so when you see a PM from old forum members, what you should do is to check their feedback and from there feedback you will know the kind of person they are.
But I will advise, regardless of their feedback tell them to make it public or forget about it.
And for the DT members if you are giving trust to someone, make sure the member is trustworthy because if they are involved in scamming newbies here, and the newbie says he believed the member was trustworthy because of the trust you gave the member, you too will be held accountable to some extent.
Not only old members , you can fall for any members scheme in this crypto space in general. But sometimes they can message you for something good , so it boils down to their intentions when they message you , the main reason this community was created is for us crypto enthusiasts to interact and stuff , and the forum pm is another means we can interact in this forum so make good use of it .