Will miners "steal" transactions that does not require signatures?

I've been learning about bitcoin script and the following types of transactions has caught my interest.

1. a4bfa8ab6435ae5f25dae9d89e4eb67dfa94283ca751f393c1ddc5a837bbc31b

This transaction has been spent already and required the spender to find some data that when hashed twice resulted in a given hash that turned out to be the genesis block header.

1. 35Snmmy3uhaer2gTboc81ayCip4m9DT4ko

This P2SH address has the following script OP\_2DUP OP\_EQUAL OP\_NOT OP\_VERIFY OP\_SHA256 OP\_SWAP OP\_SHA256 OP\_EQUAL. It currently sits on 0.27 unspent bitcoins and requires the spender to find a SHA256 hash collision.

These types of transactions are obviously insecure since the scriptsig does not sign the transaction, thus if you find a hash collision and broadcast the transaction publicly, miners can steal the bounty and send the funds to themselves. Therefore, this bitcoin talk thread recommends mining the block in which you collect your bounty yourself.

My question is if miners will actually do this and steal these bounties if they are broadcasted publicly. Obviously they can, but will they? That would require them to run some altered mining software that identifies these types of transactions and send them to themselves, does any or some miners do this?

Secondly, the thread also mentiones that if the reward for finding a hash collision is sufficiently large other miners may find it profitable to reorganize the chain to kill your block and collect the reward themselves. For this specific reward, it is not enough, but if the reward was big enough, would miners actually try and reorganize the chain?