Must you be paid for "no-work" time? Depending on - circumstances, answer may be YES.

First, understand that there are two sets of labor laws and regulations - Federal, and those of each state depending on where you live, not where the MTSO is located.  Your MTSO must comply with BOTH the state laws and regs that apply to YOU, and of course those at the Federal level as well.

The "no-work" situation will usually fall under what's more commonly called "on-call" time, and most states have very specific regulations regarding compensation that must be paid for "on-call" time, and the conditions under which it must be paid.  For instance, in at least five states, compensation must be paid if you are not at liberty to carry on normal "off-duty" activities - for instance, if you must be available to work at any time while "on-call", so that you're effectively prevented from leaving the house to carry on normal activities.

Does this apply to IC's also?  Actually, it may, if a labor auditor determines that an MTSO is abusing the IC classification for the purpose of evading labor laws. 

All states have a variety of labor laws that pertain to compensation - for instance, what kinds of expenses must be reimbursed (sometimes covering equipment, etc.).  I'd bet that in the aggregate most MTSOs are in violation of one or more of these laws, especially pertaining to compensation, reimbursement, etc., and the main reason they get away with it is our own ignorance of the laws. 

In the mid to late 1990s, the IRS and DOL came down on this industry with both feet for egregious abuse of the IC classification for purposes of evading labor laws.  The penalties were horrendous, and MTs were awarded reimbursement for overtime not paid, FICA contributions not paid, etc. 

For awhile, MT companies were properly chastened.  They either abandoned the IC-but-really-an-employee-I-don't-have-to-pay-overtime-or-FICA-for pretense altogether, or they drastically changed their treatment and compensation of ICs. 

Predictably, however, as soon as these agencies took their eye off the MT industry to focus on others, the misbehavior resurfaced and now we see almost nothing but IC positions once again.  It might be well for the spotlight to be swung back around on this industry once again.