Hi Luke, this will work for PDM Standard as well, because the PDM client software for both PDM Pro (EPDM) and PDM Standard is essentially the same.
I just tested this on my machine, in Solidworks go to Tools, SolidWorks PDM, Options (make sure you have the SolidWorks PDM Client addin turned on)
Deselect the option "Prompt to check out if opened in read-only mode", then open a file from within PDM Standard, no prompt shown.
Hope this helps.
Thank you - found it. Much appreciated.