I came across this sentence on Facebook the other day:
All people that used/goes to go to Boundary Community Elementary.
As far as I can tell, “used/goes to” is an amalgamation of “used to” and “goes to”, which appear parallel because they’re both followed by “to”; presumably “go to” is a continuation of “used to.” But here are the two sentences that were combined:
All people that go to Boundary Community Elementary.
All people that used to go to Boundary Community Elementary.
Where did “goes” come from? Combining the two sentences above produces
All people that go/used to go to Boundary Community Elementary.
My best guess is that the sentence was originally written as “All people that used to go to Boundary Community Elementary,” and then “goes” was inserted after the fact to take care of the present tense by someone who accidentally forgot about number agreement.