Generally speaking, if the signal is too "loud," the receiver can be damaged or desensitized; the overdriven receiver generates what would amount to a distorted signal (CRC errors or what would appear to be mal-formed frames).
You can cause additional attenuation in a patch cable by wrapping the excess around a spindle (which must be large enough to not violate the minimum bend radius of the media).
You can also purchase optical attenuators ($$).
Probably the best solution though is to just install good cable management components onto / into your racks or cabinets.
Good Luck
Scott
