If the vote looks close, Paramount would be expected to raise their bid to cover that cost.
[1] https://www.sec.gov/Archives/edgar/data/1065280/000119312525... 8.3(a)
Either way, this entertainment merger is going to get ugly. Consumers are absolutely going to get harmed either way with that clawback clause.
Arguably they promote a chilling effect around acquisitions, which does help competition: "don't try to buy something unless you're prepared to deal with a possible fallout" should result in fewer attempts at consolidating dominant positions.
I'd almost be tempted to posit that such a clause should become mandatory for deals over a certain threshold (e.g. $1bn), with amounts determined according to certain parameters.