I have attended a few presentations where Phil Dumas, founder of UniKey, described his experience winning an investment on Shark Tank. He explained that there were many unattractive terms in the agreement he received after the recording that made him ultimately decline the investment. My takeaway was that it doesn't matter what happens on the show, the real offer is more complicated.
(I have never seen the show, so I don't know how the offers are described. As an investor, I cannot imagine any offer that can be made verbally in the timespan of a television episode being meaningful.)
The shows are edited for time. Each negotiation, which airs for about ~10 minutes on the show, takes an average of 2 hours to shoot (with a surprisingly wide variance).
It's meaningful in getting future guests/contestants to be willing to appear on the show. If all of the sharks only ever said no, nobody would want to go on the show. They have to at least make the audience think deals are happening to keep an audience. After that, if the deal actually completes or not are not relavent to the producers of the show. They just need to line up the next round of chum to bring out in front of the sharks.
(I have never seen the show, so I don't know how the offers are described. As an investor, I cannot imagine any offer that can be made verbally in the timespan of a television episode being meaningful.)