We present several cases of optical observations during gamma-ray bursts
(GRBs) which resulted in prompt limits but no detection of optical emission.
These limits constrain the prompt optical flux densities and the optical
brightness relative to the gamma-ray emission. The derived constraints fall
within the range of properties observed in GRBs with prompt optical detections,
though at the faint end of optical/gamma flux ratios. The presently accessible
prompt optical limits do not require a different set of intrinsic or
environmental GRB properties, relative to the events with prompt optical
detections.Comment: ApJ accepted. 20 pages in draft manuscript form, which includes 6
pages of tables and 2 figure