The right word

Due to construction in downtown Houston and numerous changes to the convention center this year they have posted people in various places holding this sign.  It’s a nice thought and very helpful (the upper floor of the convention center is laid out a little odd and with all the changes it is confusing).  However, every time I see one of these signs I want to grab a Sharpie marker and cross through the word “can”.  It’s driving me crazy!  The correct phrase is “How may I help you”  MAY is the correct word.  I can’t believe they made all these signs and no one caught the error – that’s sad.