I would rather prevent them before they happen by worming in the fall rather than picking off eggs. Then of course there is always the stray bot fly (cuz your neighbors do not worm) and since the adult fly is only there to deposit eggs on your horse (and not feed on your horse) they are looking for an ideal place to lay. Just about any great skin conditioner that leaves a silky residue on the hair coat runs them off and back to the neighbor's horses.
Seems like when my neighbors moved all my bot issues dissapaered with them and their horses. But I can not think of a legal way to force anyones neighbors to be gone....so maybe not an effective means of bot control for most.
I thought I read somewhere that if you vinegar rinse them (the vinegar at the approximate pH of saliva(the bot egg "thinking" that it has been licked by the horse) that they will detach and fall off...I wish I could remember the details. I will have to do an internet search.
The thing about smart people, is they look like crazy people, to dumb people.