I will add some to Wyliecat post.

South Point ramp:  High risk-Do not leave anything valuable in your car.  Lighting is poor.  Remote location.  Lock your trailer to your hitch.  Arm your car alarm if you have one--people may not hear it though.

Buster Boyd Ramp:  Better but the police don't patrol as much in the winter as the summer because the density of bikini sporting babes is much less in the colder months.  Good ramps, well lit and lots of people around usually.  Take your chances at night.

Big Allison Ramp:  High risk:  Poor lighting.  If you see broken glass in the lot proceed to Ebeneezer Park or Buster Boyd.  Just asking for trouble if you don't.

Ebeneezer Park Landing:  Your best bet!  South end of the lake on the main channel.  The best ramps and  best security on Lake Wylie.  There is a small launch fee from Memorial Day through Labor Day (it is worth it...just ask Dieter).  Gated and patrolled by Park Ranger.  Does not eliminate the risk of vandalism but with the other ramps available why would a crook try here.

Nivens Creek:  Another place to lose your stuff to vandals.  Just avoid this one after dark if possible.  Remote and poorly lit.  Maybe only saving grace is that not too many frequent it.

Copperhead Island:  Ran by the Meck Parks and Rec.  Charges a big fee to launch, is remote and not the best lighting but probably better than SP, Nivens or Big Ally.

I hope this will prevent someone from losing some valuables.

Ranking of best to worst in my humble opinion

Ebeneezer Park
Buster Boyd Access
Copperhead Island
Big Allison Creek Access
Nivens Creek
South Point