This seemed to be a not uncommon sight in various well trafficked parts of Japan such as shopping districts, tourist attractions and transportation nexii. I'm not at all certain of the social or cultural implications of monks begging is, but they stand silently as statues with their faces covered and bowl outstretched. If you give them something you can expect a silent, respectful bow instead of a thank you. The monks don't have the same feel as say the unemployed or homeless begging do. There is an air of almost pious nobility to them, so whenever I passed one, I would donate a little something.