phildirt,
The directors of our club and those who moderate the forum are constantly monitoring forum posts and listening to members.
Financial members have long felt that there are many "freeloaders" who use the forum which is, after all, paid for by financial members through their club dues.
There have been many suggestions as to how "freeloaders" access to the forum could be restricted compared to members who, of course have full access.
Suggestions includeded
Limiting the number of posts a non member could make,
preventing non members from uploading photographs,
plus many other ideas.
To implement any such ideas would require us to spend money (your dues) to modify the package software that is used for the forum. 
We had adverts on the old website and when we discovered that we could turn on adverts for non members but allow members advert free access, it was a no brainer.
Members get advert free access whereas non members contribute (albeit a small amount) to the club through the small revenue we receive from Google for having adverts on
our website.

Google determine the adverts which are displayed based upon the individual users preferences and websites that they frequent although they should all fall within social., moral and ethical standards.

To answer your question, I do access the forum periodically as a non member would and the adverts that I have seen are broadly relevant to our website and club and I have seen no offensive ones.

I am not certain exactly how much revenue the club receives from Google for the adverts on our website but it will be 10's of dollars a month at most.
Bearing in mind that our club is just emerging from almost having to close a few years ago, we need every $ we can get.

If every member could find a fellow enthusiast and persuade them to join the club we would be in a much better place. Perhaps you would like to start this process yourself ?