If a bill bears signatures of persons for any reason cannot bind the person who signed the bill or on whose behalf it was signed, the obligations of the other persons who have signed the bill are non the less valid. (Article I, Section 7 BECA). Cited provision expresses one of the key principles of the bill law - principle of independence of bill statements. Effects of a particular signature thus do not depend on the fact whether a statement of particular debtor is binding, or not, resp. whether even undersigned presumed debtor exists.
The act states examples of non-binding signatures only in a demonstrative way; it concerns for example wrong signatures, signatures of fictitious persons or signatures of persons for any reason incapable of binding. It does not exclude a case when pertinent statement would be invalid for reasons stipulated in general provisions (in particular Sec. 37 par. 1 of the Civil Code which considers legal act as invalid on condition that it was not undertaken in a free or serious way).
As concerns obligations of other debtors, it is not essential if any other participant did not for any reason become a debtor. For instance, even if there is as a drawer stated a person who is not capable of binding himself, as an acceptor a fictitious person and his aval did not used his true name, but a pseudonym, the paper still can be - on condition that it complies with regulations on requirements of bills - binding for other debtor or debtors (endorsers).