Maybe you should do a little better research before posting what you did.
Because, if you know a little about the sharemarket and takeovers, you'd soon realise that what you wrote is not true. Especially if you won't do a very selective search.
Most, if not all, of the takeovers, are initially made conditional and then turned unconditional when it suit the bidding party, or when the bidding company reach a set level.
They can also turn/change it very quickly and most shareholders that have sold their shares while believing in the conditional side of thing, gets caught out unexpectedly.
I am not going to say here which one was the last company that attemped/pulled that stunt, but there have also been times that the bidding company was made to return those shares simply because the shareholders that sold to them, weren't given the opportunity to reconsider their actions.
Cheers
ADE Price at posting:
20.0¢ Sentiment: Hold Disclosure: Held