Ron Gilbert is trying to work something out as he wants to make something else with the series, but even he's doubtful it would happen.
When they filmed a nature documentary about Lemmings they decided to force them off a cliff as it would be more dramatic, killing them in the process. That's where the rumour got started that Lemmings throw themselves off cliffs because they're stupid. This was back in the late 50's.
Other incidences are recorded on various websites, including several deaths that occured at their theme parks.
http://www.anomalies-unlimited.com/Disney.html