Settle The Wreckage says:
Exile all attacking creatures target player controls. That player may search his or her library for that many basic land cards, put those cards onto the battlefield tapped, then shuffle his or her library.
I recently got this played against me on Magic Online, however I had just scryed a card I wanted to the top of my library and I didn't need any more land. As a result I did not want to look for land or shuffle my library.
Magic online didn't give me any choice here though and shuffled my Negate away from me. Is that correct? By my reading of the card the entire second clause is a "may" so I should have had the option not to?