The motion blur will probably give it away. Accurate video motion blur is computationally expensive but conceptually simple. Just render at about 100 times your target frame rate and average batches of frames together in linear colorspace. You can speed this up by rendering at a lower frame rate (e.g. 10 times your target frame rate), estimating motion, and blurring along the motion vectors before averaging the frames. You can further speed it up by using an adaptive frame rate depending on motion speed and contrast. But a lot of rendered video doesn't even try. Look at a fast-moving bright point of light and you'll easily see the difference.

(But note this is only replicating video, not reality. Truly realistic motion blur requires ultra-high displayed frame rates beyond the capabilities of current hardware.)