No way that roboprez trick is so dirty, I already thought was pretty dirty with quantum deconstructor spam but I never knew I could just nudge him into the water
Ecdysis (a Silent Hill runner) is the reason why we recently found this out with Roboprez. This is what prompted me finding Silhouette's dunking around the time this run was done. It does ruin the story though: it makes Armquist look like the most competent of the three bosses.
If you mean during the first mission, I did that as a backup when I missed the first throw (I've always sucked at those cow throws). The problem with just picking them up is I'll need to pick up twice as many cows (which takes time and they'll have to be weaved through to get line of sight on the next cow(s)) and they sometimes take time to die on landing, so it can be inconsistent unless you take more time to slam them down instead of flicking them up.