Real randomness would not give interesting results. You know where to go to see random filters applied mercilessly to random pictures 
A way to achieve randomness:
A way to achieve randomness:- * Add layer, and Filter>Render>Cloud>Solid noise, use largest Y and smallest x
- Filter>Blur>Pixelliize, small height (height of the strips), width of layer, to make exact horizontal bands
- Start curve, and apply any contrived curve across the histogram to make sure you have true whites and blacks
- Use ofn-shuffle-tiles to shuffle the bands
- Apply to initial layer as a displace map