I voted "yes," but in the end the yes/no decision boils down to a case by case basis on who is applying to join Signs 101. It's a very complicated situation.
We have our own ideas of what makes a sign maker a real, qualified sign maker and some of that comes from our own backgrounds and perspectives of where we're working in the industry.
From my own point of view I don't like companies who aren't real full service sign makers trying to take work away from me or further push down the wage scales of graphic designers. Window tinting outfits, printing shops or even freaking Sam's Club all try to dabble in sign making from time to time and undercut real sign makers. Then there's those volume outfits that have an army of traveling high-pressure salesmen hocking garbage signs to unsuspecting small businesses.
I don't have much regard to the self-taught amateurs trying to run a cut rate sign company from their residential garage. It's one thing if the person has the professional work experience and education to be qualified to start his own shop. Typically that's not what's happening. Most often it's someone with very little talent for graphic design jumping in from a get rich quick money making angle. A garage sign maker at least has to invest in things like a large format printer or vinyl cutter and software to control it.
Self-taught amateurs passing themselves off as graphic artists often have minimal investments in hardware, nothing in terms of formal education or training and zero dues paid to jump into the business. Just illegally download some apps and fonts and hit the ground running. And then real sign designers like me get to deal with the rancid looking results when asked to incorporate the garbage into a permanent sign that's going to visually assault the landscape for years to come. The graphic design profession has been twisted into something more like a Karaoke contest. It's Happy Camp where every child is an artist and everyone gets a gold star!
I'm not too worried about beer distributors making their own banners. Their stuff is typically ugly, but it's temporary. I don't really see what they would be bringing or taking away from discussions at Signs 101. A small business practicing home made "self signage" is probably too cheap to worry about either. A real sign company can't really afford to waste time on the cheapskates.
I'm not too worried about prison sign shops either since they're mainly making license plates or big green signs for Interstate highways.
I have no problem with a major corporation who has its own in-house sign development team as long as they know what they're doing. I've encountered some that know their stuff and others who don't. Generally none of these guys are trying to take work away from me. Often they have too much work to handle or they need someone local and competent to get a specific project done right.
Not all "real sign companies" are immune from my flames. More than a few of them staff their design departments and other areas of the operation on the basis of the cheapest wage. Despite most sign ordinances requiring UL or similar listing on electric signs (National Electric Code also requires this) many sign shops are still building electric signs that are not listed, not compliant with code and even flat out dangerous. I'm highly suspicious some of the "lowest price" oriented companies are paying their employees cash under the table and off the books to dodge taxes and insurance costs. Some may even be hiring workers who are in the country illegally. If most home builders, roofers, landscapers, custodial operations and other industries can hire illegal migrant workers, why shouldn't sign companies hire the same people? Outsource the design duties to some folks in India and insource illegal, off the books labor for the stuff that needs to be done locally.
In the end, all I can do is keep my nose to the grindstone doing the best job I can. The amateurs and cheapskates all come and go very fast and very frequently.