I have a huge sharpie and plenty cardstock that I'll bring with. Super easy to write your # on the cardstock then just tape it to your scooter and off you go.
I might be able to bring some numbers 6" or 9" for free. If letters are needed let me know. Would 50 of each number be enough. They are vinyl but not real durable. Should work well for DW. Blaack and I might have some red