Can I bring a scooter in to Arlington or do you rent them there?

Check with Arlington directly.

I don't think so, but if you need one for disability reason's then your best solution is to contact Arlington direct

I don't think they allow that because i saw some people bringing their bikes and locked them outside

When you say scooter? I am not wiite sure what you mean. If you mean a means of grtting around (like the scooters at walmart) then no. On my recent visit, i saw nothing of the sort.