They make up a big enough proportion of the search market that whether or not they'd ultimately prevail, a move like that would tie them up in anti-trust battles for the next decade.
They can choose to not deliver "enhanced" search results -- showtimes, links to buy tickets, links to IMDB/RT/etc., that appear outside of the "native" search results.
As long as they don't mess around with the native search results, they'll be safer from an anti-trust perspective.
Doesn't matter - it'd still be "trivial" to put together a sufficiently complicated case to have it survive dismissal attempts and drag it out for years.
The point is they're not just at risk of losing an anti-trust battle, but simply of having their execs embroiled in it for years.
