In fact, anti-gravity related technologies are not kept secret. It's definitely not possible to make the actual technologies public, but the related research and development content and major discoveries can still be made public.
For example, the anti-gravity shield.
This discovery has already been publicly reported, so it definitely can be made public.
By the time of the Association meeting, the Institute of Mechanics could release some research information that can't be obtained externally, thus gaining greater fame. It would also gain more say within the Association itself.
The latter is very important.
