Joseph: I agree but with a caveat. Sephardim generally wear a kippah for davening and eating (from what I recall they are strict to wear a kippah when making brachot).
GH: I grew up in a Young Israel shul where many members were not observant and we needed to keep both kippot and talleisim in the hallway of the shul. As you stated, I never recall anybody being criticized for not having their own kippah or tallis.
To answer the OP, I stated they are likely less observant then those who always come to shul but out of respect (as T22T commented) will wear it for religious functions inside of a shul. The OP use of the word “minhag” is inappropriate for this situation.