4 man gank bot

Be aware of how many globals they have. If they have shen, TF, and a dive heavy jungler (vi) then they'll most likely 4-5 man dive you. Which in that case, help your support ward deep so you can prevent the jungler from ganking and possible know where enemy mid laner location is. If there's a TF and shen on the enemy team then it's a bit more difficult cause they can almost instantly appear in your lane. I would say play passive for the most part and just forfeit tower when they're all there or when the tower is almost dead.

Tell your mid/top laners to push hard, or at least ping their lane turrets so they don't waste time coming down to bot lane (unless they have a chance with TP). The idea is to punish the enemy for putting 4 people in one lane.

If it's happening regularly, make sure you ward the tri and dragon area to help escape before they get there. (This won't work against global/long range ultimates though, so be aware of enemy team composition.)

Let your turret fall if they insist on a 4-man push. Don't try to defend it, just run away or else they will dive and kill you.

http://lolfansite.ml/index.php?threads/4-man-dive-bottom-lane.21/ I wrote some tips and ideas about this on my site.

if u had proper vision u should be able to detect 4 man gank. even including the global tele ganks. bot should be well lit first 15 min of game as in 3 wards on map . 1 pink 1 regular 1 trinket. consistently this can be done by a support alone. even at the cost of delaying of getting an item each return a lane should buy a ward.