Please, for new members, I would like to make it clear, that this topic, was posted, with a view to encouraging some robust discussion regarding the issue of signatures. This sometimes involves some articulate and equally contentious responses, but, by no means should it be seen as anything else other than a discussion.
To Bernard, I will say this. I wish that you had not felt it necessary to ameliorate your comments. Within the context of this topic, they were fair.
I'm sure that no offence was meant, and none taken.
With that said, back to topic.
Clearly there are conflicting needs.
Once someone has peeled off a label, is it possible to identify a piece of glass?
Even if the label has gone, does a signature guarantee anything?
On a brocante here in France today, was an Iittala Festivo candle-stick,
with 80% of the original transfer label missing, but a well-known and documented design. One problem with it was that it was signed with a poor dremel-inflicted TS signature to the base.
Timo Sarpaneva designed it, but a signature on a piece of pressed glass?
I bought there an unsigned piece of glass. No makers mark, few of Inwalds factories products carried a mark, and where they do, that is usually an indicator of a particular factory.
In this instance, it was a 1940 design, by Rudolf Schrotter, produced at Rudolfova Hut', during the Nazi occupation of the Sudetenland. It bears no signature but is identifiable, none the less.
In some respects, there is little difference between art glass and industrially-produced glass. If it arrives without labelling/acid-etched mark, a signature, then for the uninitiated, it can be a daunting task to find the designer, or maker of company which produced the item.
Even the presence of a label can be unhelpful. Last year I bought four pieces of Helpringham Glass. Other than the label, there are no signatures, and because this small art glass workshop disappeared after a short period of time, the information regarding the studio is sparse, its glass-master, known to be Japanese, but beyond that nothing.... In this situation, having a signature would still be irrelevant, there is nothing to relate it to. Yet, If I see work by the same hand, I will know where it came from, if not, the as-yet un-identified maker.
This is a challenging topic, with people bringing very different perspectives to this debate.
For that, I thank you all for your contributions.