TBH I don't think multiaccounting matters outside of bonus abuse -
Sportsbooks have betting limits that can potentially be evaded via multiaccounting. Wager limits are put into place in order to reduce the likelihood that betting will become too one-sided such that the sportsbook stands to lose if there is a particular outcome.
They can adjust the odds until it's no longer one-sided.
Wish bookmakers were able to hedge their bets and win the juice from each game, each betting type etc.
In reality, very few games-if any, are not one-sided. There are many reasons for this.
For example, there are 200 bookmakers that are using betconstruct software, another 100 using sbtech software etc. When you place a max bet on Kissamikos to win at bookmaker A who is using betconstrust platform, what will happened after? Betconstruct will lower the odds. But hey, there are 199 more betconctuct books who now offering lowered odds for Kissamikos, without even accepting a single penny in that team.
If same punter place a max bet on Juventus to win at same betconstuct bookmaker, what will happened? Nothing! Betconstruct will continue offering same odds for Juventus as they are following bet365 odds who is following Maxbet odds for those mainstream games. Yet, the betconstruct bookie who accepted the max bet will end with one sided game.
Few years ago there was a myth that asia bookmakers have high limits, accept winners etc and that their profit was arising from juice so they were not profiling players. Few years later we saw Sbobet and Maxbet getting rid agents, we saw asia bookmakers void winning bets by simply calling them ''abnormal bets'', we saw pinnacle cutting limits in almost every market etc.
It is obvious that bookies can't handle smart action. Imo they never had that ability. Only pinnacle may be able to to this for mainstream games. In less known leagues, they are forced to take position as well.