While online petitions to save books in danger of cancellation are common, a current petition (which now has 84 signatures) reverses the usual polarity of such events in a "man bites dog" sort of way by asking Marvel EIC Axel Alonso to cancel the Marvel Now title Avengers Arena, which the petitioners see as a tacky attempt by Marvel "to ride the coattails of The Hunger Games’ recent success." 

Launched just last month (December), Avengers Arena focuses on 16 budding superheroes who are mysteriously transported to Arcade’s Murderworld where they are forced to fight each other to the death in Hunger Games/Battle Royale fashion.  So far three of the young heroes have met their demise, and the petition also requests that the deaths of these young heroes be retconned out of the Marvel continuity. (It should be noted that the Darkhawk, who was apparently killed in Avengers Arena #3, does appear in a graphic for the second Avengers Arena story arc that starts in April, bringing up the question of whether Darkhawk is actually dead outside the confines of the game--see "Marvel Teases Two More Story Arcs").
Check out the petition itself, which is on the change.org Website. While the actual petition is very respectfully worded, the comments of some of the signers reveal that some Marvel fans are very unhappy with Avengers Arena, which is referred by one petitioner as "a horrible and obvious cash grab," while another finds that "copying The Hunger Games and Battle Royale demeans Marvel."
Will the petition have any effect on Marvel’s editorial decisions?  Perhaps it could if the petition gains some momentum, but circulation numbers drive decisions about canceling books, and as long as Avengers Arena is selling well it is unlikely to be cancelled, and it also appears unlikely that Marvel permanently eliminate 15 members of the young generation of heroes it developed in the Avengers Academy series.  But even if Marvel doesn’t cancel Avengers Arena in the near term, fans of the characters who are meeting their demise in the arena shouldn’t despair--asking a Marvel editor to retcon the deaths of comic book characters is like asking Homer Simpson if he wants another doughnut.