First an answer to a question you did not ask. Several years ago I had a kidney removed. My doctor knew I went to the parks often. He told me that for the next six months when I went, if at an attraction there was a sign warning pregnant mothers, people with bad backs, or people with heart conditions from riding it would also apply to me.
Now a few questions and answers:
Are you disabled? Yes, although temporarily.
Do you need assistance (such as an
ECV) for stamina problems? Yes!
Are you fully capable of walking through the parks, realizing that once around World Showcase at Epcot if about 1.25 miles? No!
Do you, and people with you, realize you have a disability and require assistance? Yes.
Is there any reason why any stranger should care about the fact that you are using an ECV? No.
Even if some stranger should care about the fact that you are using an ECV, is there any conceivable reason why you should care what that person thinks? No!!
I hope this helps put your fears/concerns to rest. By the way, if I am ever questioned about my use of my (personally owned) ECV I will
sweetly tell them I would be willing to give them the ECV if they will also take all my disabilities.