348.30 Securing and Supporting.(A) Securely Fastened. FMC shall be securely fastened in place by an approved means within 300 mm (12 in.) of each box, cabinet, conduit body, or other conduit termination and shall be supported and secured at intervals not to exceed 1.4 m (41/2 ft). Exception No. 1: Where FMC is fished.
Dropped ceiling with removable panels just means laziness...
Mark Heller "Well - I oughta....." -Jackie Gleason
We just went thru this with a store, the LV guy fished the camera cables, no permit, just one problem the fire, and construction offical were in the store at the time, finally they caught a live one, the store owner was not very happy, paying to have it done right.
And if it was piped in say E.M.T. it would only have to be supported every 10'. I have to agree with everyone else here, do it right the first time and support the flex to what the code calls for. Good luck.