It's confusing to me how this evolved to "Masks don't protect you but do protect others." This may be debating semantics a bit, just IMO. Indeed, my initial statement was overly simplistic and too absolute as a quick response to the original poster's comment, but the data does indeed support a much higher benefit to the person who would potentially inhale the expelled particles vs. the inverse situation, an unmasked individual expelling particles which are inhaled by a mask-wearer. But, my secondary point remains the same, especially in the context of which the original poster raised the question. I won't attempt to speak in absolute terms for the poster's motives or intention and will leave it to him to clarify if he finds it necessary, but as I initially said, I think the DHS statement is meant to clarify that mask wearing alone doesn't allow for unsafe behavior and ignoring of the other public health guidelines, and, IMO, also serves as a caution that there are numerous studies to support the reduction of exhaled/outgoing particles due to mask use, while there is less consistent data regarding the success rate of incoming filtration, which is largely dependent on the quality/material of the mask being worn. As such, they're implying that you can't view wearing your gaiter mask, for example, and expect it to be your sole preventative measure just because 'you have a mask on'. Especially in a society where many people aren't wearing masks, making even those with one on vulnerable to some degree. I think that's the real issue they're hinting at. Again, IMO. As I don't want to misinterpret your inquiries on the subject, what IS your view on mask effectiveness?