Pollock opened the scoring for the Pilgrims in the fourth minute, with Cameron equalising for the Magpies two minutes later.
United, with newest signing Sam Long between the sticks in the first half, were made to work hard for the draw against one of the National League promotion favourites - but had their own moments of joy in the second period.
Boston (3-4-2-1): Sam Long (Rhys Davies 46); Trialist A (Ben Pollock 46), Luke Shiels, Jean Leroy Belehouan (Lebrun Mbeka 46); Keenan Ferguson (Ellis Myles 46), Brad Abbott (Tom Solanke 46), Will Atkinson (Jake Wright 46), Alex Brown; Scott Pollock, Jordon Crawford; Jaanai Gordon. Subs (not used): Owen Sheriff, Trialist B.
Referee: David Coote.
Attendance: 722 (136 visitors).
PIC: Russell Dossett.