However, the obvious exceptions to those rules come in the better-grade trotting races and the country cups.
The latter often draw genuine Alexandra Park-type horses to the grass because the cups series culminates in a $25,000 final in April.
The Wild Card (R8, No 10) and to a lesser extent Jessies Cullen (No 9) epitomise that today.
The Wild Card has been racing the likes of Bettor Cover Lover, Jivin Cullen and NZ Cup runner-up Highview Tommy lately so drops a long way in class today.
His standing-start manners aren't always the best but being the sole backmarker off 40m should give him plenty of room to step away safely.
If he does the small field means he should not be too far off the leaders starting the last 1000m and he really should win.
Jessies Cullen is a much improved mare though and her trainer-driver Peter Ferguson has been looking forward to getting her to the country cups since she resumed this season.
It would surprise if one of the pair didn't win today's Te Awamutu Grass Cup.
The backmarkers are also worth following in the main trot as again they have been racing in far stronger fields.
Moment Of Truth (R7, No 15) has won 17 races, the latest four starts ago when he beat open-class opponents at Alexandra Park.
He has won twice on grass and if he produces his best today is impossible to go past.
Over the sprint trips though punters should be hunting for good draws and those dropping in class and the best example of that is Abraxas (R3, No 1).
He raced at the highest juvenile level last season and as a three-win horse it is surprising to even see him competing at today's meeting. He has enormous gate speed and should lead and win with trainer Cran Dalgety's travelling foreman Murray Howard in the sulky.
Those looking for value early could do worse than Lorcan Knight (R2, No 3), who was luckless at Wanganui last start and looked to have more to offer.
Kippenberger (R6, No 4) doesn't get penalised for his last start win so has to be tough again in one of the better betting races of the day, where Bettor Arden (No 9) and Overlap (No 5) look chances as well.
And the Peter Scaife-trained pair of Brooke Brad Carolina (No 1) and Christian Acropolis (No 2) have the draws to dominate race nine.