What do you mean by suspension clamps? Normally, I would think of coil compressors, such as those that Matt describes, which are used to change shock springs on McPherson style struts. They usually come in pairs, but you have to be careful to keep them directly opposite to each other on the spring. I did have one slip round, but there was no sudden release. I just had to slacken them off a bit and reposition.
The other possibility are those suggested by Ninja, clamps you permanently install to lower the car. These are not recommended since they apply a permanent force to a relatively small length of the coil. With plenty of driving, the springs will be considerably weakened.