Not scare tactics at all if you think about the process required.
There are many travelling who will have selected their seats (paid for of course) and then there are those passengers with reduced mobility who have to be allocated seats which then leaves us with the remainder to sort out.
There are a finite number of seats left and an intricate pattern left with which to place the remaining passengers. As has been stated previously, if you are at the front of the queue at check-in then it is more likely that you will get seats together, this includes sitting across an aisle pair of seats.
As the check-in progresses the seats remaining become more varied and although the check-in staff do have experience and training in allocating the seating (although you may sometimes find that hard to believe) it gets to a point when the last of the passengers arrive in a group travelling together and expect to have seats together on the aircraft find that it isn't going to happen. This is especially true for the harassed family with small children running late.
If you really want to sit together with no uncertainty then it would be prudent to pay up and select the seats that you want.
