The inability to PM as a new member is a negative in the sense that it means that people have to share their private details in a public forum. Doesn't sit well with me.
I recommend throwaway emails for initial contact with a seller/buyer and then give them your details.
Once your details gets crawled its going to be a hell for you.
Also, I am not one to blame victims of scams, but not having PM available for new members is merely treating a symptom. New user scammers are typically automated setups, grabbing unto basic details of what you need and then going "Yes I have ______, very good condition, selling very cheap." Not hard to spot.
I like those types the most as you can see them on a forum literally using the same sentence but with various different products.
Also, if you are the type to post your email addresses in forums, get a nice secure one with a good filter. Like mailbox(dot)org