If a Rebbe, no matter what grade level, makes a mistake, he should be told about it. I had an issue like this last year and contacted the Sgan Menahel who handled the situation.
WTP: I understand your position on neigel vasser as I too was brought up with washing at a sink. I would not stop my child from washing by the bed if they really wanted to. My children’s beds are not so close to one another so I don’t have to worry about them spilling water on the bed (on the floor, probably yes). However, your question “is it proper chinuch to set up water bowls by their beds just during the next 2 weeks of the campaign?” may have an answer that can be derived from the Shulchan Aruch/Mishna Berurah.
http://www.hebrewbooks.org/pdfpager.aspx?req=14166&st=&pgnum=141
The Mechaber in 453:1 states that during Aseres Yemei Tshuvah one who is not nizhar in Pas Cusim should be zaher during these 10 days. The Mishna Berurah adds Pas Palter. I don’t know what your family does but if you do follow this halacha for these 10 days……then yes, it would be proper chinuch to allow them to wash by the bed for the two weeks of the campaign.
I know it’s not the best proof but…