no tensioner 8 wheel belt drive: tooth skip ?

[de_]

If you accurately drill bearing holes using WCPs belt distance calculator and the 2 cim transmission power is split between 2 belts (each to a wheel and then to another wheel via a 2nd belt) and the bot is driven aggressively (ie can push and be quite fast) and the wheels are cantilevered immediately off a frame (as opposed to supported at both sides by a frame)....

Will the 15mm belts (on 24 tooth pulleys) stretch enough over the season to need a belt tensioner or replacement (else they skip pulley teeth) during the season ?

I'm also concerned the axles with its 2 bearings (in a 1" wide frame) might twist slightly introducing slack in the belt leading to tooth skip.

I heard at least one team say theirs lasted the season with no tensioner and no belt replacements. What was your experience (how many wheels, cantilevered or not, belt type, width) ?

Thanks