My recommendation would be to fly USAirways out of LGA. Terminal C is NoS-Free at both C/Ps. I prefer to use the C/P by the shuttle gates (east end of terminal) and have never had any shenanigans.
Other *A carriers out out of LGA are in the Central terminal, which, from what I understand, have NoS.
Take a look at the sticky thread in this forum for an up-to-date list. ^