Verdict: Unconfirmed.

In a thorough systematic review of interventions for school refusal by Maynard et al (2015) (also reported in Maynard et al, 2018), this strategy is indeed mentioned (pg 15):

... reducing the young person’s access to items and experiences at home which might otherwise positively reinforce the refusal to attend school ...

In general, school refusal is treated using standard psychological interventions such as cognitive behavioural therapy (CBT), and possibly medication. Since CBT and the like are "package" therapies - that is, they are customized for each patient from a broad collection of available strategies - determining if the specific strategy in question contributes to treatment effect would require a component analysis. Given that school refusal is a very niche area with few studies (the above review found 8), hope for a component analysis looking at the effect of this specific (infrequently used) strategy on school refusal is very very low (Elliott & Place, 2019).

The review also quotes another author:

"... the search for a definitive behavioural technique or group of techniques to suit all cases is inappropriate. … every case is unique and will require slightly different emphases in treatment."

For example, if school refusal is primarily associated with anxiety, then a boring home environment will do little to address the underlying issue. Thus in any case, I would not apply this strategy universally.

Verdict: Unconfirmed.

In a thorough systematic review of interventions for school refusal by Maynard et al (2015) (also reported in Maynard et al, 2018), this strategy is indeed mentioned (pg 15):

... reducing the young person’s access to items and experiences at home which might otherwise positively reinforce the refusal to attend school ...

In general, school refusal is treated using standard psychological interventions such as cognitive behavioural therapy (CBT), and possibly medication. Since CBT and the like are "package" therapies - that is, they are customized for each patient from a broad collection of available strategies - determining if the specific strategy in question contributes to treatment effect would require a component analysis. Given that school refusal is a very niche area with few studies (the above review found 8), it is unsurprising that no such analysis has yet been performed (Elliott & Place, 2019), let alone one testing the effect of this specific (infrequently used) strategy.

The review also quotes another author:

"... the search for a definitive behavioural technique or group of techniques to suit all cases is inappropriate. … every case is unique and will require slightly different emphases in treatment."

For example, if school refusal is primarily associated with anxiety, then a boring home environment will do little to address the underlying issue. Thus in any case, I would not apply this strategy universally.