I spent 5 years as a B772 Capt flying routes that were not generally thought of as subject to stowaways. Thus preflight walk rounds did not involve looking closely into the main wheel wells. Why? They are about 12 feet above your head and there is little to see with the doors shut.
On one or two occasions I felt it necessary to have the main doors "dropped" to the open position but this requires a "procedure" and the engineers would try to avoid doing that because it could cause a delay.
If you need a proper look in the '77 wheel bay you need to work at it.....