Illegal? Depends on your city's ordinances. I would avoid going on the afternoons or weekends, though, just because if there's kids around there are likely parents around to freak out. Try to go when there are few/no people around and if there are people, don't approach the person with your snake. If they approach and are curious then by all means, educate. The herp industry can use all the help it can get in that regard.