Yes for example in Ukraine many people who do border runs keep a few Euros with them in the case of any eventualities. But they are only interested in those who stay over 90 days, if you do you will likely be arrested and will need to pay a fine in the region of 50 euros.
The Balkans borders are very lenient, never heard of anyone having problems
The Balkans borders are very lenient, never heard of anyone having problems