Latisse comes with a set of "specially designed" sterile applicators, which Lumigan does not. I suppose there are workarounds for that but this fact, together with other good reasons enumerated, seem to make it unlikely Lumigan will be substituted for Latisse.
The lack of a furnished applicator with Lumigan probably wouldn’t stop someone with a penchant for experimentation; similar applicators are probably easy to come by.
On the other hand, the litigation concern cited by srsmgja strikes me as a deal-killer. Prescribing an off-label product (Avasin) for a serious medical condition such as AMD is much easier to justify (to a judge and jury) than prescribing an off-label product for a cosmetic indication.
“The efficient-market hypothesis may be the foremost piece of B.S. ever promulgated in any area of human knowledge!”