i was trying to come up with idea if teasing is long-time profitable or not
i have checked last 10 season in sportsdatabase and the over/under margin has been within 5 points in 21 % of the cases
for an average capper, that hits 55 %, this would mean that 21% of his losses have the chances to be winners if teased up to 5 points. so in 45 losses per 100 plays that could at best be 9 more wins. Or per 100 place this would result to 64 winners vs 36 losses.
When not teased the 55 winners x 1.909 ratio (European) would result in 5 % profit per 100 plays
in the teasers case we will have 64 winners with 1.52 ratio and 36 losers - generating -2.7 units loss this is the best case, but loss can be even bigger if you tease it in the wrong direction

so when they say teasers are for suckers, it is generally correct. (this is for flat betting of course)