250 grams or so of camera from 1000 feet - that's quite a big hole?!!
More like 130g including the enclosure for a GoPro and others are lighter. Plus I think the terminal velocity may be quite low. But it is a risk.
GoPro cameras and similar are regularly used in motorsport now. In the old days we had quite stringent requirements for the mounting of video cameras require steel cages and things like that, but its becoming less and less of an issue. In say a 25g impact, the restraint only needs strength of about 3.2 kgf or say 4.5 kgf with a safety factor. But there are some issues. The standard GoPro pivot bolt becoming loose under vibration is at the top of these. For motorsport, we require the tether to be used. On an aircraft this probably should not be used.