  Plenty of mid-eclipse timings of short-periodic eclipsing binaries derived
from series of visual observations appear to be an acceptable source of
information for orbital period analyses, namely if they were done in
time-intervals not covered by other types of observations. However, our
thorough period analysis of the nearly contact eclipsing binary BS Vulpeculae
proves that visually determined timings done in 1979--2003 were undoubtedly
biased to accommodate the existing linear ephemeris. The heavily subjective
character of visual observations disqualifies them as a source of true phase
information apt for fine eclipsing binary period analyses. Consequently we warn
against the use of visual timings without a preceding careful verification.
