Hey, maybe on 420 all the stoners should get together and plant as many clones as possible on a day trip. It'd be like a scavenger grow or something... Just drive around to every federal building around, planting some giant sativa clones, high as a fuckin kite, ya know?
Yes, if it is going to be done as activism, make them very visible. Having them set back a bit will allow them to gain some height before being noticed.
I wouldn't do it expecting to harvest anything in front of a court house or public planter. Just do it to shove it in their faces.
I have thought that a nice idea would be to use a planter in the center median of a major road. Think of the planters in the middle of Michigan Avenue, Chicago near Randolph. People stopped at the light in their cars would see them, but they would be a bit out of the way for pedestrians to notice. I think these would last longer. Let's also hit all the government buildings. Roll each seed in a dirt ball and toss it into a planter. I doubt anybody would know what you were up to even if seen. Your handy work would not be visible until well after the work was done.
I need a bunch of cheap seed though.
If nothing else, it will keep the agents chasing through landscaping and maybe leaving some other folks alone. They can then do their little photo ops bragging about $millions of "drugs taken off the streets by their efforts"