What are your thoughts about me taking off my shirt when doing deadlifts if I think I'm alone at the gym?
What is the reason for you needing to take your shirt off?
I just need to do that, plus it's summer
As long as the gym allows it you can take you shirt off at the gym. Some places may prefer for you to have shirts on the entire time you are there. Just be sure to check with whoever owns and runs the gym.
Yeah, it's summer so I'm going to do it
You should remove your shirt only if it does not go against the dress code of your gym. Whether or not anyone else is there, you should always follow the dress code.