No one said you couldn't take them together, you can do whatever you want. It's just not recommended, and that is on every website that sells prescription Cialis and on Lily's website. Not sure where you researched NEF, but it's plastered all over, including legit websites like epocrates. Cialis in itself can be used to lower BP, while not drastic, it's also individualistic. This isn't just a "Cover my Company's Ass" statement by manufacturers, it goes for any 2 products that have proven to lower BP. I am the perfect example that the combination can bring you to poor levels, but again, it's individualistic and unless you monitor yourself heavily (Majority do not), it's in everyone's best interest to adhere to the warnings.
For me, BP I just don't mess around with, anything else I usually do.
Anyway, we might be getting off topic. Back on track.