There are two types of fighters in MMA.
Guys that look to finish, and guys who don't, but will go for a finish if it is safe enough/presents itself without much risk.
Penn is a guy who likes to finish. That's why Penn has so many fans, he goes for flying knees, he goes for chokes, he goes in there trying to hurt you and put you away as fast as he can. He's exciting, when he fights sparks fly, even when fighting a guy like Fitch who is as boring as watching paint dry, he makes the fight entertaining and exciting.
To answer your question:
No, fighters like Penn won't start thinking twice about flying knees and chokes and going for the finish/kill, it is part of them to fight with passion, fight with the whole purpose of putting their opponent away. There are honestly not many fighters like Penn, it's why he's a legend and one of the best ever.
There will always be fighters who straight up want to be exciting and try to finish.