Escape spaces in generated shipment tracking URLs

Tracking numbers returned by remote APIs (e.g. Endicia) often include spaces.  Passing these straight through to a URL results in unexpected behavior when the tracking URL makes its way to the edges of the app (e.g. the shipment mailer).  Why not URI#escape the tracking number before passing it on as a link?

Before:
Tracking Information: 1111 2222 3333 Tracking Link: https://tools.usps.com/go/TrackConfirmAction?qtc_tLabels1=1111 2222 3333

After:

Tracking Information: 1111 2222 3333 Tracking Link: https://tools.usps.com/go/TrackConfirmAction?qtc_tLabels1=1111%202222%203333