I'm planning on attending the F1 race at Suzuka this year. I read the following statement in the track FAQs.
"Can I take pictures with a camera from the spectators seat?
Basically, to the extent that it does not make any troubles to other visitors, you can use the camera at the spectators' seating areas if the camera is 26 cm long or shorter at the full length (the longest place). However, if it makes any troubles to other visitors or when the area is crowded, our staff will kindly ask you to move the place, and your cooperation would be appreciated."
Does anyone have any recent experience in how ridgidly they enforce this in the General Admission sections? My 7D2 with 100-400 lens is 26.7 cm at 100mm without the hood and 45 cm at 400mm with the hood. 
Different tracks seem to have different regulations. Spa was basically no restrictions at all. The inaugural USGP at COTA said no more than 10" lens, but no one checked very closely. Have fun.

