Debbie,
This may sound like I'm coming to the aid of Andy, but it is not. I'm not a TMG user but I am a heavy GEDCOM v5.5.1 user.
Andy's 4 year old comment would today most likely be a little different than it was, but he is right on regarding "witnesses" of events, the subject of this thread (not a census). GEDCOM does not support the ASSO tag used to support these type of events and no other tag is appropriate to support the connection of an event to another individual. I use the NOTE tag to enter participants in events, such as judges, witnesses, co signers, etc.
If TMG does not export census information that is an issue you need to bring up with the development staff. That would be best done on a board at TMG not here since this is a public support board not associated with TMG.
All programs should/could do a better job of using GEDCOM correctly FIRST before generating their own tags. Most programs know nothing about GEDCOM and care little about using the standard correctly. They generally don't care, they would rather lock you into their program than give you a way to use " best of breed" software.
This is a loosing battle on my part. Many think that GEDCOM is old and antiquated, and needs to be rewritten. I don't belong to that group. I think that a carefully thought out enhancement program is in order then a strong campaign to tell software companies from the user community that unless they support GEDCOM correctly WE WILL NOT PURCHASE software that is not compliant.
EDIT: Unfortunately, most of the users of the popular genealogy programs such as FTM, Legacy, RootsMagic and others are novice users and know nothing about GEDCOM, and are more interested in the fancy wiz-bang new stuff that has little to do with basic genealogy research. They also expect that the program they are using, because of heavy sales campaigns or have TV programs, are the best to use. Unfortunately, they are not and these programs do little to educate the community in good (and universal) recording practices. The lack of universal recording practices and software that supports these practices is a major problem that would not be solved by better GEDCOM support but better GEDCOM support by the software companies would go a long way to better practices by the community.