Zaps are not falsifiable but they are transferrable. So lets use your bot farm in this circumstance. You transfer 50k sats from bot a to bot b for "virtually no transaction fee" (obviously you will be burning some amount) and you can continue to farm this around, adding to it as need be to increase visibility and make an opinion seem high value.
This could be used politically showing opinions praising one political party and/ or demonising the other having big sats attached to them to implicitly suggest that if you too hold those opinions sats will be coming your way.
If you're worried about bot farms giving 1000's of likes I don't think this problem currently exists here. Some spam filtering has already been implemented on relays but removing likes isn't going to remove spam comments which are a much bigger issue. Focussing on curating your follows as well as individually blocking people you feel aren't adding to your conversations will always be the best way to remove cheap talk from your feed.