The “money drop” scam is common in Kiev:
An unsuspecting victim picks up a dropped wallet, but is then accused of having stolen from it and coerced into paying. Pickpocketing and credit card fraud are also common.
In addition, there have been a few reports of suspected drugging of drinks in establishments in Kiev. General awareness and monitoring can help guard against these and other criminal activities. Bringing Ansnei along will surely keep you safe !
More information is available here.