Nothing wrong with a warning label
No problems with a warning label, in fact it should have one just because it is a transmitter and it is often held close to the body. It doesn't mean there is damage being done, but is it possible, yes , likely no. I work in electrical engineering and know all about the electronics involved and the facts are that while the amount of energy put out by cell phones is extremely low compared to other sources there are studies that show that extreme exposure to those levels can cause damage.
We are talking about way more than any person would do as the transmitters used in these test were run for 24 hours over a 7 day period, and if you use a phone that much you are probably brain dead already.
One thing people might be interested to learn is that regulations on the amount of signal allowed for cell phones is over double what the limit is for health standards for leakage from a microwave oven. Something held to your head isn't as dangerous as something you cook with on a counter ? Sounds backwards doesn't it.
The USA is behind on a lot of the safety warnings that other countries already have. Another example is lasers and LED, USA only warns on lasers but some of the newer LED are just as dangerous but have no warning about eye protection, the UK already has those warnings in place.