Travelling with a seat bag (or a knapsack on the seat), any security issues?

[BoatDoc]

In about 300K miles of touring, including an around the world trip, I've only had two incidents. I only use soft bags. In St. John's, Newfoundland my wife's saddlebags were taken off her bike and the contents rifled but nothing stolen. Apparently they were not interested in dirty laundry, feminine products and spare bike parts. In Prague, while we were asleep in our tent, some thieves unstaked the fly, unzipped the tent and removed our tank bags from between us. That was frustrating as the bags included our passports. Now the valuables are kept at the bottom of our sleeping bags!

[Nick]

....do you trust your fellow man to leave a bike alone?

Nope. I never leave anything that is unlocked/unsecured on the bike, unless I can see it. Hell, I even take my EZ Pass off the windshield 

[webmost]

One of my favorite things to do! If traveling with another moto rider I like to move the other riders machine to a different parking space, usually several spots away.

Its the small things...

:-)

One of the best pranks ever was when Sig and crew moved Wild Bill's boat to another dock while Bill was distracted at a fireworks.

[Zinfan]

If you are concerned then get a pacsafe net or similar.  http://www.pacsafe.com/pacsafe-120l-backpack-bag-protector.html  you could also probably run the cable through your helmet to secure it as well.

[Bravo Sierra]

So here is my 2c. Never leave anything on the bike over night that is not locked. Want some thing stolen go to a motel parking lot. So yes when touring I usually have a small hillbilly hay stack on my luggage rack atop my computer in a pelican case that is obviously locked  to the bike then a pile of small duffel bags all strapped down with buggy cords and rok straps in the most confusing and intricate manor possible. Never had a problem. The object is to make the strap down method look so complex that a honest person temped to take something would think it can't be done easily. I do not not try this in large cities. So use lots of buggy cords       

[Nic in Western NYS]

  I had my best rain pants stolen from a bag on my bike in Washington state at a marina.
 When I came back to the bike, the zipper was open and rain pants gone.

Only in the Pacific Northwest. Targeted theft of rain pants!

[tris]

You could get one of these and attach it to the helmet lock under the seat

http://www.outdoorgb.com/p/Pacsafe_120L_Backpack_Bag_Protector/?utm_source=froogle&utm_medium=directory&utm_content=GBR&currency=GBP&country=GBR&SelectedBundle=185887&SelectedItem=699322&gclid=CJXkvZyamdACFRG6GwodRgQHTw

As a minimum it would slow the "Ne'er-do-well" with a desire for your gear down

[Waltr]

Years ago in Wichita I had two helmets stolen. One was in the lock and they cut the chin strap. So what are they going to do with a helmet with no chin strap?
GliderJohn

I had a bike cover stolen Wichita and a leather tool kit in Kentucky on the same trip.  So much for the Bible belt.

[lorengo70]

I travel with a tail bag attached with bungee cords plus a bicycle chain combo lock through the handles to "deter" any passers by while i stop to get something to eat. The tail bag is a roll up bag and the chain is wrapped tight so they can't open it (the could cut the bag with a knife, I guess, but if they are that desperate then they can take it).  I take  to the the motel at night. 

Pic of my set up below (notice blue chain around the bag):