When somebody opens an account, he gets a certain amount of points ( it is usually 20 points on weekdays and 220 on weekends) which can be used for purchasing assets (up to 30% of the price). This "signing fee" has an "expiration day", so it should be used soon. This could be the case here, if your customer is a new member.
As for your other question about opting in for discounts...
Well...there are pros and cons on each side. I don't think there is a universal "good" answer for that.
You can try both to see what comes with them.
It is your call to decide.