Learn a lesson from Carnegie Hall: they had an autographic ('actually-written-by the signer') letter from Tchaikovsky framed on their wall until someone realized its worth and stole it. Reportedly it later appeared on a European auction site and sold for $100,000! Your items may not be worth that much, but sure as shootin' someone will prize them more than you do, so make sure "irreplaceables" are not on display; put only photocopies or recreations of them on display.
For lesser items you must still keep them behind thick glass or plastic, unless you are able to hop onto the Net and order a replacement item for overnight delivery when your item is again stolen simply because it is easy to steal.
Don't think that your good and kindly managemant style will preserve your exhibits or the theatre itself. When I advised the 1895 PABST Theater not to put an irreplaceable 1960 painting of the theatre out without being behind glass, they scoffed at the possibility of damage or theft in their classy theatre, but since they hung it on the wall in the lower lounge it has had its original attached "Pabst Blue Ribbon" literally ripped off, and now that the frame is openly scarred it is only a matter of time before vandals desecrate or steal the remainder of the painting. Visible damage has the effect of inspiring more vandalism, as is well known!
In the former WARNER there were ornate, 2-foot-long tassels hanging beside the velour draperies and someone just pulled one of them hanging within ten feet of the seats, down and somehow smuggled it out of the building. It may not have been so vital as to close the theatre, but it left an unbalanced effect, and such decor costs around $2,000.00 EACH to be custom remade these days by such as Scalamandre Silks! Of course, it was never replaced.
Sooo, your dear patrons may make hash of your exhibits and decor unless you carefully plan their protection first! After you plan protection you can plan welcome artistry.
[This message has been edited by jimor (edited June 27, 2006).]