In The Netherlands, there was an automatic fine to be paid to anyone who filed a FOI-request and didn't get the answers or requested information within a pretty short period. The inevitable result was the rise of small companies dedicated to filing as many obnoxious requests as possible, They reworked the law recently to tone that down a bit.
Also, someone used this law to harass a council with multiple requests per day over a period of more than a year, leading to the department having 4 full-time staff to answer just his requests. Finally, a judge limited him to only a few requests per week. He refused to obey and he was jailed as a consequence.