If you attacked straight up with your secondary same team account you would likely dry up your potions. Does Instinct really ever fill all 6 slots? (Yellow is actually very strong in my immediate area, other parts of town weak)
Who cares if you make it tougher on the other team? (game is super simple already) An issue is taking slots from your team in stagnant areas, but n/a. I mean you had to somewhat play to get it to 24, not like you bought an extra 35 and put 3100 Snorlax. At some point an opposing team could beat you with the same Exeggutor. I do think it gets a little shady and anti-competitive concerning berry feeding through the weaker account though, if that were a regular practice
***The obvious reason to have a double same color was to make your color stronger, knock down a tower then double place to prestige and add just a couple speedbumps. In most places Instinct needs the help, what you might look to is: the Vaporeon you place, is it above average for what (non-battling) players put in---for example: they might roll by and put in furret or maybe the average player actually cares to put a bigger Lapras in