In Italy a very important role in the last 20 years, in stressing the importance of correct labelling with the nursery trade, was played by specialized garden fairs (specialized meaning focusing on smaller nurseries, not for the big market). I have been organizing one such, in La Landriana Gardens near Rome, since 2001 and we made a point of giving recognition, sometimes a prize, a special mention, a medal or so, to nurseries that correctly labelled their plants. In the beginning we had to be strict: during the event exhibitors were invited to remove wrong labels, were in any case blamed if their labels were not correct, were not admitted to competitions such as best plant or best stand design etc., if they had not labelled appropriately, and slowly through the years wrong-doers were isolated or grew out of their incorrect approach.
In short, we stressed the issue as much as possible, and things started to change.
During the following years many gardens fairs were established throughout Italy, and many follow those principles; I can say now that the fairs did somehow produce a general growth in awareness - even though the results were slow to take hold, and there has been a sort of regression recently, due to the crisis and the many set backs it brought .
I have always wondered if there is anything like this in other Mediterranean countries. Do Greece, Cyprus, Spain or Portugal have garden fairs? I remember discussing this possibility with Sally Beale when we went to Mallorca at the 2011 AGM., and not surprisingly (knowing her managing skills) a couple of years later she told me that she had succeeded in organizing such an event over there.
Well, wherever there is a network of local garden fairs, MGS branches could participate to those events and promote awareness: run a competition/offer a prize (give a medal, issue a parchment roll or a honor award, tie a ribbon, and promise a mention on the website) to encourage and commend nurseries that expose correct labelling during the show, and make sure to have this mentioned on the local garden magazines, radio, tv, internet and press releases.
Maybe we could produce recommendations, such the ones that you have been talking about in this thread; they should be distributed in connection to the garden fair awards, i.e should be printed out on a leaflet and given to the nurseries that will exhibit in that fair. The recommendations could also be made downloadable form our website.
The branches could then produce a list of awarded, commendable nurseries that label correctly on their homepage , to further encourage others nurseries to adopt correct procedures.