The definition of participation as spam belongs to the mod/admin and how the user poses the question. Therefore, it is difficult to set guidelines to limit this, especially since some people deliberately violate BTT rules, either because they want their ads to appear or to increase their rank.
Mostly new users ask a question why the post was deleted and then they will get the answer with a link to the forum rules.

Many of these problems will be avoided when welcome message is released.