  Fermi-LAT spectra at high energies (HE, 0.1-100 GeV) are often extrapolated
to very high energies (VHE, >100 GeV) and considered either a good estimate or
an upper limit for the blazars intrinsic VHE spectrum. This assumption seems
not well justified, neither theoretically nor observationally. Besides being
often softer, observations do indicate that spectra at VHE could be also harder
than at HE, even when adopting the limit of Gamma=1.5. Results based on such
straightforward GeV-TeV extrapolations are in general not reliable, and should
be considered with caution.
