As a Modern Day wet plate photographer, I make images of Civil War reenactors.  I do both ambrotypes and tintypes.  It is very important to realize that there are thousands of these images being made every year in the US and the UK.  Learning to tell the difference between an image made in the 1860's and one made in the 2000's can be very difficult, but essential.  The wet plate collodion process is very archival. It will seldom show the patina and wear one associates with an antique...especially if the image has been kept in a case.  Many antique images can look as perfect as the day they were made, and many NEW images can look antique when they are presented in a misrepresenting way...that is, remounted in an antique case.  How do I tell the difference, you may ask.  Well, first off you need to study as many genuine images as you can.  Look very carefully at the individual in the image.  The average 19th century man existed on a much different diet than the typical civil war reenactor of today.  He was much leaner, with a hard bony look to the face and cheeks.  Many times you will see a shadow below the nose, at an angle.  This is a hallmark of a skylight studio...something that hardly any modern photographers have.  Most modern photos on glass are done on window glass, which has a standard thickness of 1/16th inch and will be very flat and plane, both front and back.  A very faint smell of lavender may also be detected on most modern images....this is the varnish which takes a long time to dry.  A slight scratch with the fingernail may make this smell more apparant.  Very few modern photographers use black alphalt varnish to blacken the rear of the plate, but most 19th cent. ones used this technique.  Look also for faint traces of tarnish and discoloration where the mat has lain.  This is difficult to reproduce.  Few photographers today can do the very fine gold tinting on buttons very well.  Colored glass was used in the 19th century, known as ruby glass.  It is fairly thin, and has the color of plum.  No glass is made today just like this.  Black glass, used by many modern photographers was not available during the CW era.

Be very wary.   The danger is not really with the images in the hands of the subjects (reenactors) but probably with the next generation who does not realize they are not antiques.