Originally posted by Maelstrom That and lockouts on the wrong type of bike can damage the frame as it is built to move and not to be solid.
Most good air shocks... specially ones with lockouts have a blow-off valve to prevent you from doing something dumb like keeping the shock locked-out while hitting a 5' drop. That said, I agree with Maelstrom's caution. You still need to be careful. The blow-off theshold may be too far above what the frame was designed for.