Is it permissible to go out with a friend on their birthday for leisure, not celebration, and is that considered a pretense?

The fatwa on this site is that it is impermissible to celebrate birthdays or offer congratulations for them. The Sharia evidence indicates that celebrating births (mawlid) is an innovation (bid'ah) and a newly introduced matter in religion, and it involves imitating the Jews and Christians. There is no difference between holding the celebration at home or elsewhere. If going out for a picnic has no reason other than celebrating someone's birthday, then it is precisely going out for the celebration, and one should not participate with them in that. Some scholars have determined that what is forbidden to do is also forbidden to witness.