it is a concern for so many people. there's been a lot of work done in that area and certainly over the inauguration, that's restricted air space. so, i would advise any of your viewers not to have any of those up in the air. >> experts tell cnn authorities can now intercept and land droenz, and even use radio frequencies to track the operators. >> i'm not going to go into it, but we do have certain capabilities to detect and defeat devices of that nature. >> and official are expecting dozens of demonstration groups on inauguration day. the washington post site 63 groups both pro and con expected to be in attendance. as you heard they are prepared if anything gets out of hand. the secret service will only intervene if there is a direct threat to the president. jake? >> a big, big security challenge. pamela brown, thank you so much. that's for me and "the lead." cnn films was allowed unique access rarely seen by the public as part of a documentary, the end, inside the last days of the obama white house.