how hard is it to get a penta kill?

i had gotten many quadras(by many i mean many) myself and seen plenty of penta on my teammates and enemies, but was never able to get a penta. it felt like every time i got a quadra the only remaining eneny in the other side of the map will immediately recall and camp fountain. but when the enemy got a quadra my teammate seem to be extremely nice and gives the penta to the enemy for free.

what do u guys think?