depends on where your going
and how your travelling
when i played in france a few year's back
i went by train through the tunnel
on booking in was asked what was in the bag
i told them what it was and where i was going
was then asked to put everything together
as they had not had a paintball marker go
through before
three xrays, four photo's and twenty minutes later
i was allowed to travel
but i had a guard with me all the way
all i can say is be honest declare what your carrying
things have changed since then
as to insurance
get everything valued properly
inform your insurance company before hand
you may be able to get your kit insured
with the same company as your house insurance
but phone around
hope this helps