I was in the U.S. military stationed in Spain. In our initial military briefing when our airplane landed, we handed over our U.S. Government red passports to the Spaniards who kept them until we rotated back to the States. By that if we got into any trouble while in Spain, they could hold us, like prisoners.
In our briefing we were warned about dealing with the Spanish public, as we didn't have diplomatic immunity. We were told there was a G.I. that got drunk in Madrid and caused a car accident that killed a Spanish citizen. He was in their Spanish prison.
When I left Spain, finished my tour there, that G.I. was still in Spanish jail three and a half years later. U.S. ambassadors to Spain were still trying to get him out of Spain's prison.
Anyone doubting how much harsher foreign countries outside the U.S. are on foreigners should watch the movie Midnight Express, a true story about Bill Hayes who got caught smuggling drugs in Turkey. He was going to be in prison for life, until somehow he escaped.