Please tell me how you interpret this?

Actually, it's just one sentence, but I'll type the whole pasage anyway just to give you some context:

"I don't know how she managed it, but, for all the time they were at Nauheim, she contrived never to let those two be alone together, except in broad daylight, in very crowded places. If a Protestant had done that it would no doubt have awakened a self-consciousness in the girl. But Catholics, who have always reservations and queer spots of secrecy, can manage these things better. "

The part I'm having trouble understanding is "who have always reservations and queer spots of secrecy."

Does the world reservation here mean reservation as in a reserved table in a restaurant? And "spots of secrecy"? Does it mean places where one finds private, like when they don't like to be disturbed?

Any help is appreciated. Thank you1