I just read the post... And I agree with the sentiment of the two last posts.
Russia, in my experience wasn't the worst place for dodgy police and border crossings officials although I had to pay some money to cross the border and while there.
It revolts my stomach every time someone in authority use it to gain for himself. I've heard all the excuses yet I don't think any of them condone what these police and custom officials do. They spoil it for everyone and give their countries and countrymen a bad name most don't deserve.
I think it is everyone's duty to try avoid paying.
There are tactics that make the likelihood of paying much smaller and I think that's helpful info, rather than telling someone he has ben naive or arrogant.
These are the strategies that worked for me:

You don't understand them (even if you do). Do not speak their language (even if you know how to). Be polite, smile and wear their patience down without being confrontational. Often, the sad truth is that for every minute they waste with you they are loosing other potential 'customers'. I used to tell them that we have Pesetas in Spain and I didn't know about 'dalars' or 'yuros'; their interest drop to nearly cero on hearing of a currency they didn't know. Lasst resort, take their vehicle licence or other identifiers, call your consulate and they might negotiate on the mobile for you (they will know if they are asking 10 times the worth of a fine and shame them) if you have to pay you're likely to pay a lot less. Contact bikers clubs through HU. They will know mechanics and safe places to park bikes. On borders, come back later when there is a different officer in charge, may be less greedy and also shows your determination not to given something for nothing.
Try to make them laugh or smile. A smile and polite and friendly attitude combined with a refusal to pay confuses most of them because they expect anger; then, they know they also have to negotiate with you.

Remember, if you don't pay, they are less likely to bother the next guy.
If you have any tips on avoiding bribes that worked for you, post them please. Id love to hear them just in case I ned to use them!
I hope this helps.

__________________
Smile