I think I see where Kioka is coming from. While the flight response of an animal kept in a trough style/open top enclosure isn't unnatural it is likely to be stressful. Whereas a monitor kept in an open front enclosure sees people at eye level and is more likely to behave normally. Also I'm thinking that when put that way most of us would agree. I do think that depending on the monitor they're likely to lose the flight response as they grow to recognize their regular keeper. I've kept monitors (and tegus) that were so comfortable that flight would be the last thing on their mind, and if anything they'd jump up to get to the food they probably figure is coming...while the one V. salvator I've kept would probably never have been comfortable in an open top enclosure like that. Just depends on the animal.