I take Multi-Symptom Immodium (the kind you chew) whenever I have symptoms and am going out in public. I can deal with it at home but it really helos me when I am out socially. I think it's fine to take and has really helped me - I don't take it often because I am afraid it will stop working :) and also if I am really having that many symptoms I should be at home anyway.
The main reason I think anyone would tell you NOT to take it would be if you had something like c. diff or some sort or toxin that the body was trying to eliminate through the D.
Otherwise, Immodium is great. The Muliti-Symptom helps with gas and bloating, and that is what starts to make me run for the bathroom. Drink lots of water with it too!!