Spousal visa for someone who breached immigration rules?

[poling213]

I'd like to ask for advice on the following scenario:

Non-EU citizen takes up a 12 month Masters program with a Tier 4, and worked during that summer vacation. She later found out she wasn't supposed to work as a Masters student. She then left the UK for 1.5 years.

She is now back on a 9 month course with another Tier 4 visa, and wants to get married to a British citizen.

Will they be able to refuse her spousal visa application since she has breached immigration rules in the past? But then again it doesn't seem as though the HO care, as she was still granted another Tier 4 visa after 1.5 years. Should she disclose this in her spousal visa application?

[Dorkey]

How did she find out that she's not permitted to work as a Master's degree student? All students are allowed to work during school term not more than 20hours a week and can work full time during the holidays. I did my Master's degree with a Tier 4 visa which states that permitted to work 20hours during term time and I worked throughout my degree period.